Lawrence Berkeley National Laboratory
University of Tokyo
Giacomo Claudio Ghiringhelli
Maria Novella Piancastelli
Bongjin Simon Mun
Gwangju Institute of Science and Technology
Diamond Light Source
University of California Davis, Lawrence Berkeley National Laboratory
Max-Planck-Institut für Kernphysik Heidelberg
Forschungszentrum Jülich, Peter Grünberg Institute
Department of Quantum Matter Physics, University of Geneva and Swiss Light Source, Paul Scherrer Institute
Johannes Gutenberg University of Mainz
Shanghai Institute of Applied Physics, CAS
Friedrich Alexander University Erlangen-Nürnberg
University of Tokyo
Jin Feng Jia
Shanghai Jiao Tong University
Diamond Light Source
Kenichi L. Ishikawa
University of Tokyo
L. Andrew Wray
New York University
Institute for Molecular Science
University of Illinois at Urbana-Champaign
European X-ray Free-Electron Laser
Swiss Light Source, Paul Scherrer Institute
Lawrence Berkeley National Laboratory
Synchrotron X-ray Station at Spring-8, National Institute for Materials Science (NIMS)
Peter D. Johnson
Brookhaven National Laboratory
Dalian Institute of Chemical Physics
Lawrence Berkeley National Laboratory
Lawrence Berkeley National Laboratory
RIKEN Center for Emergent Matter Science
Japan Synchrotron Radiation Research Institute/Spring-8
Swiss Light Source, Paul Scherrer Institute
Center for Free Electron Laser Science, Deutsches Elektronen-Synchrotron
University of Science and Technology of China
Institute of Physics, Chinese Academy of Sciences
Soft x-ray dichroism is a powerful method to investigate the local electronic and magnetic states of solids. We have developed an apparatus equipped with a vector magnet for magnetic field angle-dependent dichroism measurements, and installed
it at a twin helical undulator beamline of Photon Factory. Using this system, we study the origin of magnetic anisotropy (MA) in correlated transition-metal oxides such as ferromagnetic manganites and their thin films , where MA is
controlled by epitaxial strain from the oxide substrate. Through measurements of x-ray magnetic circular dichroism (XMCD) with varying magnetic field angle including the transverse geometry, one can extract the anisotropic distribution
(i.e. quadrupole moment) of spin-polarized electrons. We have indeed detected a finite anisotropy of spin distribution that depends on the strain, and concluded that the MA is due to a combined effect of anisotropic spin distribution
and spin-orbit coupling, leading to the anisotropy of orbital magnetic moment, known as the Bruno model. (The model breaks down in heavy metal-3d metal alloy films .) As a reverse process of the strain-induced MA, we have detected
a field-induced anisotropic electron distribution by x-ray magnetic linear dichroism (XMLD). Application of angle-dependent XMCD to ferrimagnetic spinel oxides which exhibit Mott transition and charge-orbital order has given information
related to their cubic MA .
 G. Shibata et al., npj Quantum Mater. 3, 3 (2018).
 K. Ikeda et al., Appl. Phys. Lett. 111, 142402 (2017).
 Y. Nonaka et al., arXiv:1802.07074; to appear in Phys. Rev. B; unpublished data.
Atsushi Fujimori is a professor at the Department of Physics, the University of Tokyo. He received his B.S., M.S, and D.Sc. degrees from the University of Tokyo in 1976, 1978, and 1981, respectively. He was a research scientist at National Institute for Research in Inorganic Materials, Tsukuba, Japan, between 1978-1988, and a visiting assistant professor at the University of Minnesota, USA, between 1984-1985. He has been studying the electronic structure of correlated electron systems, including transition-metal compounds, high-temperature superconductors, and rare-earth compounds by photoemission and absorption spectroscopies using soft x rays and VUV light.
Resonant inelastic soft x-ray scattering huge potential is quickly becoming reality. RIXS is element and site selective, like x-ray absorption spectroscopy. It is momentum resolved, like x-ray diffraction. And it probes several kinds of
excitations at a time, from charge transfer and electron-hole pair generation, to orbital (dd or ff) excitations, to spin waves and lattice modes, unlike any other energy loss spectroscopy. Moreover, the elastic component of the spectra
carries information on commensurate and incommensurate orders, such as charge density waves (CDW) and orbital order. The ERIXS endstation at the ID32 beam line of the ESRF is the founder of a new generation of RIXS instruments capable
of exploiting all the strongpoints of this technique, thanks to the very high resolving power (30,000 at 1 keV), the diffractometer-like manipulator and the full control of photon polarization provided by the combination of the APPLE
II source and the polarimeter on the analyzer. Similar facilities are starting operations at DLS, NSLS II, MAX IV, TPS, to the greatest benefit of beamtime availability worldwide.
I will review some of the results obtained in the first years of operations of ID32, with a special focus on cuprate superconductors studied at the Cu L3 edge. High resolution RIXS has been used to determine the relation between crystal structure and the extent of hopping integrals in parent compounds, revealing why apical oxygens are detrimental to superconductivity . Ultra-high resolution RIXS has provided a direct measurement of the momentum-dependent electron phonon coupling in undoped and superconducting samples, and has revealed new collective modes related to charge density waves (CDW) in underdoped Bi2212 . Polarization analysis has definitively demonstrated the spin-flip character of the mid-IR spectral region in superconducting compounds. And the quasi-elastic part of RIXS spectra has brought new evidence of the universality of charge ordering phenomena in cuprates, including striped cuprates  and single layer Bi2201; in particular, by RIXS the charge order can be observed and carefully studied also outside the pseudogap region of the phase diagram, with significant progress in the understanding of its role in high Tc superconductors.
 Y. Y. Peng, G. Dellea, M. Minola, M. Conni, A. Amorese, D. Di Castro, G. M. De Luca, K. Kummer, M. Salluzzo, X. Sun, X. J. Zhou, G. Balestrino, M. Le Tacon, B. Keimer, L. Braicovich, N. B. Brookes and G. Ghiringhelli, Nature Physics 13, 1201 (2017).
 L. Chaix L, G. Ghiringhelli, Y.Y. Peng, M. Hashimoto, B. Moritz, K. Kummer, N.B. Brookes, Y. He, S. Chen, S. Ishida, Y. Yoshida, H. Eisaki, M. Salluzzo, L. Braicovich, Z.X. Shen, T.P. Devereaux, and W.S. Lee, Nature Physics 13, 952 (2017)
 H. Miao, J. Lorenzana, G. Seibold, Y.Y. Peng, A. Amorese, F. Yakhou-Harris, K. Kummer, N. B. Brookes, R. M. Konik, V. Thampy, G. D. Gu, G. Ghiringhelli, L. Braicovich, M. P. M. Dean, PNAS 114, 12430 (2017)
Giacomo Ghiringhelli is Professor of experimental physics at Politecnico Milano (Italy), and visiting Scientist at the European Synchrotron (ESRF, Grenoble). Expert in x-ray spectroscopy of strongly correlated solids, in the last 15 years he has led the development of high resolution resonant inelastic x-ray scattering (RIXS) for the study of spin and charge order in high Tc superconductors and of associated excitations.
The ‘tender’ x-ray domain, from 2 to 13 keV, has recently become available for atomic and molecular studies at the French synchrotron SOLEIL on the GALAXIES beam line with state-of-the-art photon and electron energy resolution. The
GALAXIES beamline is dedicated to inelastic x-ray scattering (IXS) and high energy x-ray photoemission (HAXPES) in the hard x-ray range. The beamline is designed to pro-vide a monochromatic and microfocused beam with the highest
flux possible in the 2.3-13 keV spectral range and an adaptable energy bandwidth between 50 meV and 1 eV.
We have investigated there a wealth of new phenomena by means of photoelectron and Auger spectroscopy. The list includes recoil due to the photoelectron’s momentum [1,2], ultrafast nuclear motion on the femto- and sub-femtosecond time scale [3,4], double-core-hole studies [4-8], novel interference phenom-ena [9-12], ultrafast photodissociation in the Auger cascade following deep-core ionization [13,14], direct derivation of potential energy surfaces  (see also  for a recent review).
Another key experiment has been performed at SPring-8, Japan, where even higher photon energy is available, which has allowed us to measure for the first time the Xe 1s photoelectron spectrum .
We demonstrate that the newly accessible extended photon energy range does not simply allow studying more systems with deeper core edges, but opens a totally new horizon in what concerns electron and nuclear dynamics of deep-core-excited and core-ionized isolated species.
 M. Simon et al, Nat. Commun. 5, 4069 (2014)
 E.Kukk et al, Phys.Rev.A 95, 042509 (2017)
 M.N. Piancastelli et al, J. Phys. B: At. Mol. Opt. Phys. 47, 124031 (2014)
 R. Püttner et al, Phys.Rev.Lett. 114, 093001 (2015)
 S. Carniato et al, Phys.Rev. A 94, 013416 (2016)
 G. Goldsztejn et al, Phys.Rev.Lett. 117, 133001 (2016)
 R. Feifel et al, Sci.Rep. 7, (2017) 13317
 D. Koulentianos et al, Phys.Chem.Chem.Phys. 20, (2018) 2724
 D.Céolin et al, Phys.Rev.A 91, 022502 (2015)
 R.K.Kushawaha et al, Phys.Rev.A 92, 013427 (2015)
 G. Goldsztejn et al, Phys.Rev.A 95, 012509 (2017)
 G. Goldsztejn et al,Phys.Chem.Chem.Phys. 18, 15133 (2016)
 O.Travnikova et al, Phys.Rev.Lett. 116, 213001 (2016)
 O.Travnikova et al, Phys.Rev.Lett. 118, 213001 (2017)
 T.Marchenko et al, Phys.Rev.Lett. 119, 133001 (2017)
 M.N.Piancastelli et al, J.Phys.B: At. Mol. Opt. Phys. 50, 042001 (2017)
M.N.Piancastelli et al, Phys.Rev.A 95, 061402(R) (2017)
Maria Novella Piancastelli is full professor at the Department of Physics and Astronomy, Uppsala University, Sweden. She graduated at the University "La Sapienza", Rome, Italy. Since then, she filled several academic positions in Rome, Berlin, Berkeley, and is presently guest professor at the Sorbonne University in Paris. Her main research interests cover photoexcitation and relaxation dynamics of isolated atoms and molecules, primarily with synchrotron radiation and more recently with free-electron laser sources. She has chaired several international conferences, including the ICESS conference in Rome in 1995. She is Fulbright Fellow and American Physical Society Fellow.
Experiments in the time domain allow to determine the electron-boson coupling strength by analyzing the second moment of the Eliashberg function α2∙F(ω) using the relaxation time constant of thermalized, hot electrons after optical
excitation.  While this approach works well for conventional superconducting materials, it is under discussion for unconventional superconductors due to competing electron and boson dynamics on similar time scales. [2,3] It
is therefore desired to identify well defined bosonic or electronic signatures in time-resolved spectroscopy. In this talk results of femtosecond time- and angle-resolved photoemission on cuprate and Fe-based superconductors will
be presented. Experimentally observed, well defined boson signatures [4,5], which originate from restrictions in the relaxation phase space  will be discussed. We show that coupling to specific bosonic excitations, which were
identified by ultrafast electron diffraction for the case of Bi-2212 to consist of in-plane lattice vibration,  inhibits thermalization of the excited electron distribution. Such microscopic insight provides opportunities to
analyze the electron-boson coupling directly, without the assumption of a thermalized electron distribution.
 Brorson et al., Phys. Rev. Lett. 64, 2172 (1990).
 Perfetti et al., Phys. Rev. Lett. 99, 197001 (2007).
 Baranov and Kabanov, Phys. Rev. B 89, 125102 (2014).
 Rameau et al., Nature Commun. 7, 13761 (2016).
 Avigo et al., New J. Phys. 18, 093028 (2016).
 Kemper et al., Ann. Phys. 529, 1600235 (2017).
 Konstantinova et al., Sci. Adv., in press (2018).
Uwe Bovensiepen is Professor of Physics at University of Duisburg-Essen. Expert in femtosecond magnetization dynamics, non-equilibrium dynamics of correlated electron materials, and ultrafast electron dynamics in low dimensional systems.
Photoemission and in particular Angle-resolved photoemission spectroscopy (ARPES) has been an powerful tool to study the electronic properties of a wide range of materials. Until recently ARPES measurement were limited to relatively large, homogeneous samples. Now, groups at several synchronous light sources have begun developing ARPES instruments which use focused x-rays to make measurements on the nano meter length-scale. These so called nanoARPES instruments will bring the power of ARPES to a whole new range of samples. At the MAESTRO beamline of the Advanced Light Source, we are commissioning a new nanoARPES endstation which combines state of the art angle resolved photoemission (ARPES) with presently less than 120 nm, but eventually less than 50 nm spacial resolution, bringing k - and energy resolved electronic contrast at the nano- and mesoscale within reach. In this talk, I will present the current status of the nanoAPRES and show some early results on the spatially-resolved electronic structure of heterostructures of mechanically transferred monolayers of 2D chalcogenides, epitaxially grown islands of WS2 on silicon carbide, and other materials. In all cases, nanoARPES reveals a range of inhomogeneities that are both opportunities and challenges for understanding and controlling the electronic structure of quantum materials at these length scales.
Aaron Bostwick is a staff scientist at the Advanced Light Source, Lawrence Berkeley National Laboratory, USA. He is in charge of the operations of the MAESTRO beamline, and is the leader of the nanoARPES development. His research interest are primarily focused on the electronic structure and many-body physics of 2D materials.
In this talk, I will discuss how intense electromagnetic radiation at TeraHertz frequencies can be used to coherently drive quantum solids. I will discuss how one can control the electronic properties of a material and will report on a number of recent experiments in which hard and soft x-ray pulses from Free Electron Lasers have been used to probe the dynamics of lattice, charges, orbitals and spins.
Andrea Cavalleri is the founding director of the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg (Germany) and a professor of Physics at the University of Oxford (UK). He is best known for his experiments in which intense TeraHertz pulses are used to manipulated collective excitations in quantum solids, and for demonstrating that one can induce non-equilibrium superconductivity far above the thermodynamic transition temperature. He has also been majorly involved in the development of ultrafast X-ray techniques, since their inception in the late 1990s through their modern incarnation at X-ray Free Electron Lasers. Cavalleri is a recipient of the 2015 Max Born Medal from the IoP and the DFG and of the 2018 Isakson Prize from the APS. He is a fellow of the APS, of the AAAS, of the IoP, of the Academia Europaea and of the European Academy of Sciences.
The quantum anomalous Hall (QAH) effect is a quantum Hall effect induced by spontaneous magnetization, and occurs in two-dimensional insulators with topologically nontrivial electronic band structure which is characterized by a non-zero Chern number. It was first experimentally observed in the thin films of magnetically doped (Bi,Sb)2Te3 topological insulators (TIs) in 2013, more than thirty years after the discovery of the first quantum Hall effect by Klaus von Klitzing. In this talk, I will report on some recent experimental progresses in this direction. By co-doping of Cr and V into (Bi,Sb)2Te3 TI films, we are able to significantly increase the observation temperature of QAH effect. More interestingly, we can construct other topological states of matter such as axion insulator, quantum spin Hall insulator and QAH insulator of high Chern number by growing QAH insulator-based heterostructures.
Xue Qikun (薛其坤) is a physicist of Tsinghua University, Beijing. He has done much work in Condensed Matter Physics, especially on superconductors and topological insulators. In 2013, Xue was the first to achieve the quantum anomalous Hall effect (QAHE), an unusual orderly motion of electrons in a conductor, in his laboratory at Tsinghua University. Xue is a member of the Chinese Academy of Sciences, vice president for research of Tsinghua University, and director of State Key Lab of Quantum Physics. In 2016 he was one of the first recipients of the new Chinese Future Science Award for experimental discovery of high-temperature superconductivity at material interfaces and the QAHE. This award has been described as "China's Nobel Prize"
A fundamental concept in solid state physics describes the degrees of freedom of electrons in a solid by the relation of the energy E vs. the crystal momentum k in a band structure of independent quasi particles. In a real electron
system, exchange and correlation interaction are collective phenomena that lead, for instance, to effects like ferromagnetism. Consequently, for the 3d ferromagnets Fe, Ni, and Co, a description of the band structure in the widely
used local density approximation (LDA) is of limited use, as seen by the fact that predicted well defined electronic bands are not observed experimentally. Only recently, experimental access to the spin resolved band structure
at every point in the Brillouin zone became feasible by spin-resolved momentum microscopy . This novel concept combines high resolution imaging of photoelectrons in two-dimensional (kx, ky) maps with a highly efficient imaging
spin filter .
Based on this comprehensive quantitative information, we discuss tomographic sections through the three-dimensional Fermi surface of the prototypical itinerant ferromagnet cobalt, and its detailed spin-resolved quasi particle band-structure. Together with state-of-the-art one-step photoemission calculations, the combined experimental and theoretical approach allows us to quantify the complex self-energy of the quasi particle states in terms of spin-dependent energy renormalization and lifetime broadening within the complete Brillouin zone. Despite a pronounced lifetime broadening, direct optical inter-band excitations can be highly spin selective. This leads to the creation of nearly 100% polarized hot carriers in ferromagnetic cobalt, and might serve as a source of spin-polarized electron currents in spintronics applications .
 C. Tusche, A. Krasyuk, J. Kirschner, Ultramicroscopy 159, p. 520 (2015)
 C. Tusche, et al., Appl. Phys. Lett. 99, 9, 032505 (2011)
 M. Ellguth, C. Tusche, J. Kirschner, Phys. Rev. Lett., 115, 266801 (2015)
Christian Tusche carried out his doctoral studies at the Max-Planck-Institute of Microstructure Physics in Halle, Germany, and received his doctorate in experimental physics from the University Halle-Wittenberg in 2007. In the following years, he became the leading scientist of the spin-resolved photoemission group at the Max-Planck-Institute of Microstructure Physics. Form 2015, he became a senior scientist at the Peter Grünberg Institute at the Forschungszentrum Jülich and a member of the Faculty of Physics at the University Duisburg-Essen. In 2016, he has been awarded the Innovation Award on Synchrotron Radiation for his development of “Imaging Spin-Filters for Spin-Resolving Momentum Microscopy”.
Department of Quantum Matter Physics, University of Geneva and Swiss Light Source, Paul Scherrer Institute
We demonstrate strain-tuning of the metal-insulator transition in lightly doped Ca2-xPrxRuO4. For x > 0.04 we are able to fully suppress the insulating phase of unstrained samples and induce a metallic ground state. ARPES measurements as a function of strain reveal that metallicity emerges from a marked redistribution of charge from the xy orbital, which is completely filled in the Mott state, to the initially half filled out-of-plane xz/yz bands. Concomitant with the transition to the metallic state we observe a sudden collapse of the spectral weight in the lower Hubbard band. The ground state of the metallic phase is a heavy electron liquid with a well defined Fermi surface which is devoid of pseudogaps but shows signatures of strong hybridization indicating an important role of spin-orbit interaction
Félix Baumberger is professor of physics at the Department of Quantum Matter Physics of the University of Geneva and at the Swiss Light Source. He obtained his PhD from the University of Zurich in 2002 for work in the group of Profs. Osterwalder and Greber. Following postdoctoral studies with Prof. Z.-X. Shen in Stanford he took up a post as Lecturer / assistant professor at the University of St Andrews in 2006 before moving in 2012 to the University of Geneva. In 2007 he won an ERC starting grant. Félix Baumberger is the main proposer and chair of the User Working Group for the ARPES beamline I05 at Diamond Light Source. His main scientific interests are correlated metallic states, metal insulator transitions, oxide interfaces and van der Waals materials.
Combining full-field k-space microscopy with time-of-flight energy recording has recently paved the way to unprecedented data-recording speeds . Simultaneous imaging of a k-space region of several Brillouin zones and energy intervals
of a few eV, complemented by sequential mapping of the kz-coordinate via photon-energy scans, yields 4D arrays representing the full accessible information on the spectral density in the 4D parameter space (kx, ky, kz, EB): all
energy isosurfaces (e.g. the Fermi surface), electron velocity distributions, identification of electron and hole pockets, hosting of surface states etc. Further “dimensions” are accessible by recording photoelectron dichroism
and electron spin-polarization texture using an imaging ToF-spinfilter . Generalizing the concept of the "complete" photoemission experiment  to the case of solids we encounter two scalar and one vector function in 4D parameter
space. The new approach is especially powerful for dynamical studies, adding the “pump-probe delay” as a further coordinate. We will illustrate the concept by data for the low- and high-energy range including first results taken
at the free-electron laser FLASH (DESY, Hamburg).
 K. Medjanik et al., Nat. Materials 16, 615 (2017);
 G. Schoenhense et al., Ultramic-roscopy 183, 19 (2017);
 J. Kessler, Comm. At. Mol. Phys. 10, 47 (1981)
Born 1952 in Germany; study of Physics at Westfälische Wilhelms University of Münster. Diploma 1978; PhD 1981 in the group of Prof. Joachim Kessler ("Spin-Polarization of Photoelectrons Ejected by Unpolarized and Linearly Polarized Light from Unpolarized Atoms"). 1981-1985 Research Assistant (group of Prof. Ulrich Heinzmann) at Fritz-Haber-Institute of Max-Planck Society, Berlin. Postdoctoral fellow at ETH Zurich (group of Prof. Hans Siegmann) and University of Hawaii at Manoa (group of Prof. Charles S. Fadley). Habilitation 1987 University of Bielefeld ("Spin Polarization and Dichroism in Photoemission"). 1987-1991 Associate Professor at University of Bielefeld. Since 1991, Professor at Johannes Gutenberg University of Mainz. 2001–2004 Scientific Head (on commission) of Institute of Microtechnology Mainz GmbH (IMM). (Co-) Foundation of several companies as spin-offs of the University groups; supervision of >20 Postdocs, 35 PhD and 70 Master/Diploma students; > 350 reviewed publications, 6 patents. Research profile: Surface Physics, advanced techniques of photoemission and spin-resolved spectroscopy.
Angle-resolved XPS of low-vapor-pressure liquids provides access to surface enrichment effects and allows for in situ studies of chemical reactions. We report on recent investigations on ionic liquids. In addition, our studies
addressing novel supported liquid metal catalysts will be discussed. The latter have been performed with our near-ambient pressure XPS lab setup, and with a newly developed two-analyzer lab-based XPS system that allows for simultaneous
measurements of low-viscosity liquids at normal (0°) and grazing emission (80°).
 F. Maier, I. Niedermaier, H.-P. Steinrück, J. Chem. Phys. 146 (2017) 170901 1-15
 N. Taccardi, M. Grabau, …C. Papp, H.-P. Steinrück, P. Wasserscheid, Nat. Chem. 9 (2017) 862
 I. Niedermaier, C. Kolbeck, H.-P. Steinrück, F. Maier, Rev. Sci. Instrum. 87 (2016) 045105 1
Prof. Hans-Peter Steinrück received his PhD in physics at TU Graz 1985, was postdoc at Stanford University, received his Habilitation at TU München and became Professor of Physics at Würzburg University in 1993. Since 1998, he holds a chair of Physical Chemistry at University of Erlangen-Nuremberg. He was Guest Professor at USTC/Hefei, is member of the German Academy of Sciences Leopoldina, the Austrian Academy of Sciences and Academia Europaea, and Fellow of APS and AAAS. His research focusses in surface and interface science, from ionic liquids, liquid metals, porphyrins and liquid organic hydrogen carriers to chemically modified graphene. He published 330 peer-reviewed papers. https://www.chemistry.nat.fau.eu/steinrueck-group/
Control of charge/spin states by optical excitations in magnetically ordered materials has attracted considerable attention since the demonstration of ultrafast demagnetization in Ni within 1 ps, explored by time-resolved magneto optical Kerr effect studies. For this study, we chose time-resolved x-ray measurements to study ultrafast charge/spin dynamics in transition-metal compounds. We performed a time-resolved x-ray study in a pump-probe setup by using our experimental setup at BL07LSU in SPring-8. For example, we observed spin dynamics of the FePt thin film, demonstrating photoinduced demagnetization.
Hiroki Wadati is an Associate Professor of experimental condensed-matter physics at University of Tokyo. His PhD research was the development of photoemission study of transition-metal oxides in the form of epitaxial thin films. Now he is an expert in observing ultrafast charge/spin dynamics by time-resolved x-ray measurements.
The most successful theoretical approach to deal with angle-resolved photo emission is the so-called spectral function or one-step formulation of the photo emission process. Nowadays, the one-step model allows for photo current calculations
for photon energies ranging from a few eV to more than 10 keV, to deal with arbitrarily ordered and disordered systems, to account for finite temperatures, and considering in addition strong correlation effects within the dynamical
mean-field theory or similar advanced approaches. The contribution reviews the recent theoretical developments in the field concerning the treatment of correlations, chemical disorder as well as finite temperature effects .
The second part of the talk presents generalization of the one-step model of photo-emission that allows to deal with timedependent spectroscopy on the basis of the Keldysh non-equilibrium Green function formalism . To demonstrate
the power of the new scheme results of an application to two-photon photo emission, i.e. pump-probe experiments involving surface image states on non-magnetic as well as magnetic materials will be presented. The use of the approach
to describe corresponding pump-probe X-ray absorption experiments in an analogous way will be sketched briefly.
 Braun, J.; Minár, J. and Ebert, H.; Physics Reports, 740, 1–34, (2018)
 Braun, J.; Rausch, R.; Potthoff, M. and Ebert, H.; Phys. Rev. B, 94, 125128 (2016)
Born 1955 in Germany, study of physics at Ludwig-Maximilians-University, Diploma 1982 at LMU Munich, PhD degree 1986 at LMU Munich ("NMR investigations on the electronic properties of metallic systems – Theory and Experiment"), 1986-87 Postdoctoral fellow at University of Bristol, UK, 1987-93 Central Research and Development, Siemens Erlangen, Habilitation 1990 LMU Munich ("Hyperfine interaction in complex systems and influence of relativistic effects on the magnetic and optical properties of magnetic solids"), since 1993 C3-professor LMU Munich. Expert in research fields: hyperfine interaction in para- and ferromagnetic transition metal systems; magneto-optical properties of transition metal compounds and layered systems; magnetic X-ray dichroism; phase stability of transition metal compounds; transport properties of transition metal alloys and layered systems; photoemission of correlated solids.
The talk will review our recent experimental and theoretical works in the field of many-electron spectroscopy and many-electron emission using VUV to hard X-ray energy region synchrotron radiation. The focus will be placed to the studies utilizing direct many-electron photoemission, Auger cascades and multiple Auger-electron emission, and how they can be used in the present day research of free-standing atoms and molecules.
Dr. Kari Jänkälä works as senior university researcher in the nano and molecular systems unit at the University of Oulu, Finland. He is interested in the properties of atomic scale systems ranging from single atoms and molecules to nanoclusters. His current main research takes place in the field of computational modeling of electron and ion dynamics in single and multiple photoionization and Auger decay in the X-ray photon energy region.
Today, thanks to elaboration of quantum chemistry methods, one can calculate ground-state properties of large systems containing tens to hundreds of electrons. In marked contrast, approaches for the dynamics in a strong, time-dependent external field is still in the stage of active development. In this talk we present various ab initio (first-principles) simulation methods to describe the real-time dynamics of multielectron atoms, molecules, and solids in an ultrashort and/or intense laser field.
Kenichi L. Ishikawa received the Ph.D. (Dr.rer.nat.) degree from RWTH Aachen University, Aachen, Germany, in 1998. He is currently a Professor at Department of Nuclear Engineering and Management, Graduate School of Engineering, the
University of Tokyo, Tokyo, Japan. He was a Postdoctoral Researcher at CEA-Saclay, Gif-sur-Yvette, France, from 1998 to 2000, a Special Postdoctoral Researcher at RIKEN, Wako, Japan, from 2000 to 2002, an Associate Professor at
the University of Tokyo, Tokyo, Japan, from 2002 to 2008, a Senior Researcher at RIKEN, Wako, Japan, from 2008 to 2009, and a Project Associate Professor at the University of Tokyo, Tokyo, Japan, from 2009 to 2014. His research
interests include attosecond science, strong-field physics, and ultrafast intense laser science.
In this study, we have developed a liquid flow cell for soft X-ray absorption spectroscopy (XAS) in transmission mode, in which the liquid thickness is controllable from 20 nm to 2000 nm, and studied molecular interactions in several liquid samples with the help of inner-shell calculations based on quantum chemistry. We also applied in situ XAS technique to catalytic and electrochemical reactions in liquid phase.
Masanari Nagasaka is Assistant Professor at Institute for Molecular Science, Japan. He received Ph.D degree from Department of Chemistry, Graduate School of Science, The University of Tokyo at 2007, and moved to the current position in this time. His research interests are local structure analyses of liquid samples by soft X-ray absorption spectroscopy (XAS) in transmission mode, and operando XAS observation of chemical reactions in liquid phase, such as catalytic, electrochemical, and photochemical reactions.
A central mystery in high temperature superconductivity is the origin of the so-called “strange metal,” i.e., the anomalous conductor from which superconductivity emerges at low temperature. Measuring the dynamic charge response of the copper-oxides, χ(q,ω), would directly reveal the collective properties of the strange metal, but it has never been possible to measure this quantity with meV resolution. Here, we present the first measurement of χ(q,ω) for a prototypical strange metal, Bi2.1Sr1.9CaCu2O8+x (BSCCO), using momentum-resolved inelastic electron scattering. We discover a surprising energy- and momentum-independent continuum of fluctuations extending up to 1 eV that obeys simple power-law behavior. Our study suggests the strange metal exhibits a new type of charge dynamics in which excitations are local to such a degree that space and time axes are decoupled. Implications of these observations beyond the copper-oxide superconductors will be also discussed.
Matteo Mitrano graduated in Physics at the University of Rome "Sapienza" (Rome, Italy) in 2010. Afterwards, he started his doctoral studies under the supervision of Andrea Cavalleri at the Max Planck Institute for Structural Dynamics (Hamburg, Germany). There, he worked on the photoinduced dynamics and the light-control of organic Mott insulators and superconductors, also under high-pressure conditions. After completing his PhD, in 2016 he moved as a Feodor-Lynen postdoctoral fellow at the University of Illinois at Urbana-Champaign where he works with Peter Abbamonte. His current work focuses on the charge dynamics of strange metals and on the investigation of charge collective modes in high-temperature superconductors by using both inelastic electron and soft X-ray scattering.
The availability of X-ray Free Electron Lasers (FELs), providing intensities of up to 1016 W/cm2 and pulse duration as short as a few femtoseconds, has opened various new possibilities in the study of light-matter interaction. Some
recent examples of this research on atomic systems will be discussed focusing on multi-photon processes in the short wavelength regime, such as multiple-ionization, resonant two-photon excitation and above threshold ionization
(ATI). Especially high-resolution and angle-resolved electron spectroscopy was applied to extract detailed information about the dy-namics of the multi-photon processes. In a series of investigation comparing the relative strength
of single photon and two-photon (sequential and direct) ionization processes, the above threshold ion-ization (ATI) of atomic Xenon in the region of the 4d giant resonance was studied . Supported by the theoretical analysis
of the underlying processes, the study highlights non-linear processes can bring out new information, here about so far unobserved resonant structures in the well-studied, broad 4d resonance. In addition, non-dipole phenomena in
the 3p ionization of Argon ions, pro-duced in the sequence of multiple ionization by intense FEL pulses, were investigated . The ex-periments were performed at photon energies around 55eV in the region of the Cooper minimum,
which gives rise to strong non-dipole effect already at these low energies. Generally, the results demonstrate new possibilities of experiments on ionic samples, compensating low target density by the high number of photons available
at free-electron lasers. Finally, future research at the Small Quantum Systems (SQS) instrument of the European XFEL are presented.
 T. Mazza, A. Karamatskou, M. Ilchen, S. Bakhtiarzadeh, A.J. Rafipoor, P. O'Keeffe, T.J. Kelly, N. Walsh, J.T. Costello, M. Meyer and R. Santra, Nature Communications 6, 6799 (2015)
 M. Ilchen, G. Hartmann, E. V. Gryzlova, A. Achner, E. Allaria, A. Beckmann, M. Braune, J. Buck, C. Callegari, R. N. Coffee, R. Cucini, M. Danailov, A. DeFanis, A. Demidovich, E. Ferrari, P. Finetti, L. Glaser, A. Knie, A. O. Lindahl, O. Plekan, N. Mahne, T. Mazza, L. Raimondi, E. Roussel, F. Scholz, J. Seltmann, I. Shevchuk, C. Svetina, P. Walter, M. Zangrando, J. Viefhaus, A. N. Grum-Grzhimailo and M. Meyer, Nature Communications accepted
Since 2010, Group Leader and Responsible Scientists for the SQS (Small Quantum Systems) Scientific Instrument at the European X-ray Free Electron Laser in Hamburg Germany. After doctorate at the university of Hamburg and a postdoctoral position at the synchrotron Facility LURE in France, he obtained in 1993 a permanent position at the CNRS in France, first as research associate and in 2005 after habilitation as research director. He has longstanding experiences with experimental investigation of atomic and molecular targets using various synchrotron radiation sources (DORIS, PETRAIII, BESSY II, LURE, SOLEIL, ALS, ELETTRA, UVSOR) and Free-Electron Laser sources (FLASH, FERMI, LCLS, European XFEL). Main research interests are investigations of electron dynamics in the one- and two-color photoionization of atoms and molecules, especially studies of resonant processes, non-linear phenomena and time-resolved experiments.
The success of many emerging molecular electronics concepts hinges on an atomistic understanding of the underlying electronic dynamics. Processes evolving on spatial and temporal scales spanning orders of magnitude have to be connected in order to gain a comprehensive understanding of the fundamental dynamics and scaling laws that enable molecular, interfacial, and macroscopic charge and energy transport. Time-domain X-ray spectroscopy techniques have the potential to provide a deeper understanding of electronic dynamics in complex, heterogeneous systems owing to their elemental site specificity and sensitivity to local valence electron configurations. We present femtosecond to picosecond time-resolved X-ray photoelectron spectroscopy (TRXPS) studies of photoinduced charge transfer dynamics in nanoporous films of N3 dye-sensitized ZnO and in bilayer heterojunctions consisting of copper phthalocyanine (CuPc) electron donors and C60 acceptors. Differential TRXPS line shifts provide access to transient interfacial dipoles and charge delocalization dynamics in the N3/ZnO system as well as a deeper understanding of exciton transport and charge generation mechanisms in the CuPc/C60 system.
Oliver Gessner received his PhD from the Technical University Berlin for work performed at the Fritz-Haber-Institut of the Max-Planck-Society. He became a postdoctoral fellow at the Steacie Institute for Molecular Sciences in Ottawa before joining Lawrence Berkeley National Laboratory, where he is now a Senior Scientist in the Chemical Sciences Division. His research concentrates on ultrafast dynamics in molecules, clusters, and interfacial systems, which are studied by time-domain x-ray spectroscopy and imaging techniques using high-order harmonic generation techniques, synchrotron radiation facilities, as well as x-ray free electron lasers.
Low energy, laser-based ARPES with variable light polarization, including both linear and circularly polarized, offers a powerful probe of the electronic structure near the center of the Brillouin zone. Here the technique is used
to examine the Fe-based superconductor family, FeTe1-xSex. At the center of the zone we observe the presence of a Dirac cones with helical spin structure as expected for a topological surface state and as previously reported in
the related FeTe0.55Se0.45. These experimental studies are compared with theoretical studies that take account of the disordered local magnetic moments related to the paramagnetism observed in this system. Indeed including the
magnetic contributions in the theoretical description is necessary to bring the chemical potential of the calculated electronic band structure into alignment with the experimental observations. In the bulk superconducting state
for FeTe0.7Se0.3 the system appears to reflect the presence of some level of orbital selectivity in the pairing even though the system is in the tetragonal phase above and below the transition temperature Tc. At the same time the
topological state appears to acquire mass at the superconducting transition. These observations are discussed in detail. The work at Brookhaven was supported in part by the U.S. DOE under Contract No. DE- SC0012704 and in part
by the Center of Computational Design of Functional Strongly Correlated Materials and Theoretical Spectroscopy. The theoretical studies (MW) at UWM were supported by the National Science Foundation (No. DMR-1335215).
1. P. Zhang et al., Science 360, 182 (2018)
Peter Johnson, Head of the Electron Spectroscopy Group at Brookhaven National laboratory, is an internationally recognized leader in photoelectron spectroscopy and its application to the study of low dimensional systems including both metallic surfaces and strongly correlated materials, particularly and high-temperature superconductors. For work in the latter area he was a recipient of the American Physical Society's Oliver E. Buckley Prize in 2011 and Brookhaven Lab's Science and Technology Award in 2001. After earning a Ph.D. in physics from Warwick University in 1978, Peter worked for Bell Laboratories, and then joined Brookhaven Lab in 1982. He rose through the ranks to become Chair of the Condensed Matter Physics & Materials Science Department, a position he held from 2007 to 2016. He was also the Director of the Center for Emergent Superconductivity, an Energy Frontier Research Center, which existed from 2009 – 2018. upon its founding in April 2006. He is a Fellow of the American Association for the Advancement of Science, the American Physical Society and the Institute of Physics in the United Kingdom.
The ultrafast motion of one or more electrons bound to atoms in response to ultrafast and strong electric fields can be identified as a fundamental quantum dynamic process. All-optical XUV attosecond transient absorption spectroscopy
provides a unique handle to access these dynamics. In particular, by identifying and understanding line shape changes in the XUV absorption spectrum (e.g., Fano vs. Lorentzian line shapes ) in response to strong external NIR
electric fields, one is sensitive to the NIR-driven dynamics of the electrons when they are still bound to the atom. This includes XUV-excitations of inner-shell  and two-electron  transitions, which are naturally short-lived
(Auger and autoionization relaxation pathways). In this talk I will give an overview of our most recent research in this direction. Most importantly I will focus on how to extract real-time quantum dynamic information of the NIR-driven
two-electron dynamics in helium directly from a single XUV absorption spectrum. Furthermore, I will provide a brief overview of our activities by using XUV light of a free-electron laser for femtosecond time-resolved strong-field
XUV-only transient absorption spectroscopy of helium, neon, and small molecules.”
1. Science 340, 716 (2013)
2. Optics Letters 41, 709 (2016)
3. Nature 516, 374 (2014)
Christian Ott studied Physics at the University of Würzburg in Germany and Optoelectronics and Lasers at Heriot-Watt University in Edinburgh, Scotland. He obtained his PhD in 2012 from the University of Heidelberg. With a Feodor Lynen research fellowship by the Alexander von Humboldt foundation he spent a two-year postdoc at the University of California at Berkeley, USA. Since 2016 he is staff scientist and group leader at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. His research activities include the investigation of strong-field light-matter interaction of electron dynamics driven both by lab-based (HHG) and large-facility (FEL) light sources. Techniques cover the use of attosecond transient absorption spectroscopy primarily on small systems (i.e., inner-valence, core and two-electron excitations in rare-gas atoms). Special focus is put on the investigation and control of spectral line shapes in absorption spectroscopy, recently also with intense XUV light from SASE FELs.
A quantum spin Hall (QSH) insulator, or a two-dimensional topological insulator, is characterized by quantized Hall conductance in the absence of a magnetic field. From the electronic structure point of view, the hallmarks of QSH
insulator are topologically protected helical edge states that bridges the energy gap opened by band inversion and strong spin-orbit coupling .
By combining angle-resolved photoemission spectroscopy (ARPES), first-principles calculations, and scanning tunnelling microscopy/spectroscopy (STM/STS), we have investigated the electronic structures of epitaxially-grown monolayer 1T’ transition metal dichalcogenides, WTe2, WSe2, and MoTe2, candidate QSH insulators . For 1T’-WTe2, we indeed observed the band inversion, band gap opening, and geometry-independent edge states, consistent with the expectations for a QSH insulator . While 1T’-WSe2 shares the same essential features of electronic structure with 1T’-WTe2, it is naturally n-doped to have a band gap at higher binding energy . 1T’-MoTe2 is found to have a significant overlap between conduction and valence bands due to the moderate strength of spin-orbit coupling .
 A. Devarakonda and J. G. Checkelsky, Nature Physics 13, 630 (2017).
 X. Qian et al., Science 346, 1344 (2014).
 S. Tang et al., Nature Physics 13, 683 (2017).
 M. M. Ugeda et al., arXiv:1802.01339 (2018).
 S. Tang et al., APL Materials 6, 026601 (2018).
Sung-Kwan Mo is a staff scientist at the Advanced Light Source, Lawrence Berkeley National Laboratory, USA. He received his Ph.D. in physics at the University of Michigan in 2006. He continued working on the electronic structure studies of quantum materials as a postdoctoral fellow in Stanford University. From 2010, he is in charge of the angle-resolved photoemission endstation at the Beamline 10.0.1 of the ALS. His recent research focuses on the growth of two-dimensional materials using molecular beam epitaxy and angle-resolved photoemission investigation of their electronic structures.
Dopants are very important for materials science. By adding dopants to various materials such as semicon- ductors and metals, their properties can be controlled. The atomic arrangement around the dopant is also very important. Atomic
resolution holography such as photoelectron holography, X-ray fluorescence ho- lography, and neutron holography  is very effective for seeing the three-dimensional atomic structure around the dopant. In the case of photoelectron
holography, the angular distribution of the core level pho- toelectrons can be regarded as an atomic resolution hologram. In principle, it is possible to reconstruct three-dimensional atomic images without other knowledge of the
structure. Although photoelectron holo- grams have been measured by many researchers, it was still difficult to reconstruct the atomic structure, as the previous reconstruction algorithm had several problems. We developed reconstruction
algorithms, SPEA-MEM based on the maximum entropy method  and SPEA-L1 based on the sparse modeling method . The scattering pattern function of a single scatterer atom is used an analytic function of the developed algorithm.
Since this pattern function is not orthogonal, a maximum entropy or sparse model is used. Therefore, a more accurate three-dimensional atomic image can be reconstructed. We applied this to photoelectron holograms of the dopants
in Si  and diamond crystals and determined their local structures. We also performed X-ray fluorescence holography to observe the dopant structure with SPEA-L1 recon- struction algorithm . The developed algorithm can also
be applied to other atomic resolution holography.
 K. Hayashi, et al., Science Adv., 3, e1700294 (2017).
 T. Matsushita, et al., Europhys. Lett., 71, 597 (2005); T. Matsushita, et al., Phys. Rev. B, 75, 085419 (2007); T. Matsushita, et al., Phys. Rev. B, 78, 144111 (2008).
 T. Matsushita, et al, J. Phys. Soc. Jpn., 87, 061002 (2018).
 K. Tsutsui et al., Nano Lett., 17, 7533 (2017).
 S. Hosokawa et al., Phys. Rev. B, 96, 214207 (2017).
Tomohiro Matsushita was appointed the director of information-technology promotion division at Japan synchrotron radiation research institute (JASRI) in 2017. He has worked at JASRI since 1997, and constructed the control systems for beamlines in SPring-8. He also has studied the photoelectron holography using SPring-8 beamlines and developed the software for measurement and analysis. In last ten years, he started study about x-ray fluorescence holography and neutron holography. Dr. Matsushita’s primary area of research has focused on experiment and theory for the atomic resolution holography.
Soft-X-ray ARPES enhances the k-resolving abilities of this technique with large probing depth and a possibility of resonant photoexcitation. These virtues allow stretching the ARPES experiment from conventional surface physics to buried heterostructure and impurity systems actual for device applications. I review basic principles of soft-X-ray ARPES and illustrate its applications to various solid-state systems of fundamental and applied interest such as oxide materials, semiconductor and oxide interfaces, and magnetically doped semiconductor and topological materials.
Vladimir N. Strocov has obtained his Ph.D. degree from St. Petersburg State University in 1989. His further research between Chalmers University of Technology, Augsburg University, etc. was devoted to low energy electron diffraction, giving direct access to photoemission final states, and the corresponding ARPES experiments. Since 2014 he was developing synchrotron beamline instrumentation for ARPES and RIXS at Swiss Light Source. Presently the main focus of his research is soft-X-ray ARPES in application to various crystalline, heterostructure and impurity quantum materials
High repetition rate free-electron lasers like FLASH at DESY and the European XFEL are excellent sources for time-resolved XUV and soft x-ray photoemission spectroscopy on high density targets such as solids and surfaces. In particular,
at FLASH we have recently added two new dedicated endstations for time-resolved PES which combine the high average brightness of the FLASH FEL with highly efficient analyzers and detection systems.
In the talk I will present recent examples of time-resolved ARPES and time-resolved XPS studies per-formed at FLASH which illustrate the power of this approach for the study of ultrafast dynamics.
Wilfried Wurth received a PhD in physics from the Technical University Munich, Germany in 1987. He is currently scientific head of FLASH, the first XUV and soft x-ray free-electron laser world-wide operated as a user facility, at DESY in Hamburg and professor in experimental physics at the Center for Free-Electron Laser Science at the University of Hamburg. His research interests include linear and non-linear soft x-ray spectroscopy, free-electron laser physics and instrumentation for free-electron laser science, ultrafast dynamics in solids and at surfaces.
High-order harmonic generation (HHG) from femtosecond lasers are developing into efficient and widely tunable vacuum-ultraviolet light sources for time-resolved photoelectron spectroscopy. In addition, the use of two time-of-flight spectrometers with coincidence detection enables double photoemission (DPE) where two interacting electrons are emitted upon the absorption of one single photon, the most straightforward method to probe electron-electron correlation. Here we present photoemission and double photoemission results on Ag(001) and Cu(111). For Ag and Cu, the 2D energy distribution of photoelectron pairs shows sharp sum-energy onsets, which are discussed in terms of electronic d-d, d-sp, or sp-sp pair excitations. Whereas the sum energy of each electron pair is a good quantum number, the individual electron energies are broadly distributed indicating an intense energy sharing between the electrons within a pair.
Cheng-Tien Chiang received his Ph.D. in 2011 from the Max Planck Institute of Microstructure Physics and the Martin-Luther-University Halle-Wittenberg in Halle, Germany. As a habilitation candidate in the group of Prof. Wolf Widdra in Halle, he has developed high-order harmonic light sources at megahertz repetition rates for applications to photoelectron spectroscopy. These applications not only pave the way towards efficient laboratory experiments on ultrafast electron dynamics, but also allow band-resolved spectroscopy on correlated electron pairs in solids by double photoemission. His research focuses on the electronic structure at surfaces and interfaces of transition metals and their oxides, where the interaction between localized and itinerant electrons plays a dominant role. To observe these effects directly, he uses laserbased photoelectron spectroscopy and microscopy with femtosecond time-resolution.
Center for Free Electron Laser Science, Deutsches Elektronen-Synchrotron Inst. for Optics and Atomic Physics, TU Berlin
The determination of excited electron lifetimes in solids and on surfaces is of high current interest. Knowledge about these excited states is of great importance for the understanding and control of photophysical processes, ranging
from charge generation in solar cells to photochemistry as for example photo-activated splitting of water. We here use conventional angle resolved photoelectron spectroscopy to determine these lifetimes (1,2). This experimental
technique has been very successfully employed to determine the occupied bandstructure of solids (3) to the extend that the results are by now incorporated into basic solid state physics textbooks. Angle resolved photoemission also
reveals the excited state lifetime as originally shown for Cu (4). This is based upon monitoring the intensity of well identified interband transitions as the energy of the photons is changed. As this requires some careful calibrations,
this has not been widely used so far.
Apart from the lifetime measurements, these data also reveal the existence of very strong final state resonances located approximately 20 eV above EF. At these resonances the transition intensity varies by an order of magnitude over a photon energy range of 1-2 eV. These final states are associated with bands derived from 4f- (5f-) atomic orbitals, as the demonstrated by the fact that the sp-like surface state does not couple to these final states.
As the interest in these lifetime measurements is growing, there are no obstacles to use this technique for other single crystalline materials. Moreover these measurements are complementary to the data obtained by direct as-laser techniques (5,6).
1. F. Roth, C. Lupulescu, E. Darlatt, A. Gottwald, and W. Eberhardt, J. Electron. Spectrosc. 208, 2 (2016).
2. F. Roth, T. Arion, H. Kaser, A. Gottwald W. Eberhardt, J. Electr. Spectrosc. 224, 84 (2018)
3. E. W. Plummer and W. Eberhardt, Advances in Chemical Physics 49, 533 (1982).
4. F. J. Himpsel and W. Eberhardt, Solid State Comm. 31, 747 (1979).
5. Z. Tao, C. Chen, T. Szilvasi, M. Keller, M. Mavrikakis, H. Kapteyn, M. Murnane, Science 353, 62 (2016).
6. L. Locher, L. Castiglioni, M. Lucchini, M. Greif, L. Gallmann, J. Osterwalder, M. Hengsberger, U. Keller, Optica 2, 405 (2015)
Wolfgang Eberhardt studied Physics in Giessen and Hamburg, where he graduated in 1978. He was a postdoc and Assistant professor at University of Pennsylvania and later joined EXXON Exxon Research and Eng. Co. In 1991 he was appointed director of the Institute ‘Electronic Properties’ at IFF Jülich and professor at Univ. of Cologne (Germany), in 2001 he was appointed as scientific director of BESSY in Berlin and professor at the TU Berlin. In 2003 he received an honorary PhD from Uppsala University. From 2009 to 2011 he was Director at HZB for ‘Energy Research’ and since 2011 he is at DESY-CFEL. In 2016 he retired from TU Berlin. Wolfgang Eberhardt’s Research Areas are: Electronic structure of atoms, molecules, and solids determined by photoemission and synchrotron radiation related techniques; Development of angle resolved photoemission to study the bandstructure of solids, surfaces and interfaces; Electronic structure and magnetism of thin films and nanostructures; Fs- magnetization dynamics; Electronic properties and structure of clusters; Core electron excitation and dynamic screening processes in molecules and solids; Fs-2-photon-photoemission spectroscopy of clusters and solids; Scattering and holography with coherent synchrotron radiation. Energy Research, Renewable Energies, Photovoltaics. He co-authored about 370 publications and has an h-index of 68 (as of 2018) and was granted 3 patents
In this talk, I will first introduce our progress in developing vacuum ultra-violet laser-based angle-resolved photoemission systems. Then I will report our recent results on studying high temperature superconductors and topological
materials including: (1). Distinct electronic structure and superconducting gap in (Li,Fe)OHFeSe and bulk FeSe superconductors[1-2]; (2). Quantitative determination of pairing interactions in high-Tc cuprate superconductors
and (3). Electronic structure of topological materials including ZrTe5 and HfTe5[4,5].
 Lin Zhao et al., Nature Communications 7, 10608 (2016);
 Defa Liu et al., arXiv/1802.02940 (2018);
 Jinmo Bok et al., Science Advances 2, e1501329 (2016);
 Yan Zhang et al., Nature Communications 8, 15512 (2017);
 Yan Zhang et al., Science Bulletin 62, 950 (2017).
Professor Xingjiang Zhou is currently a professor and the director of National Lab for Superconductivity, Institute of Physics, Chinese Academy of Sciences, Beijing. He received his B.S. and M.S. degrees from Tsinghua University in 1988 and 1990, respectively, and his Ph. D degree from the Institute of Physics, Chinese Academy of Sciences, in 1994. He was a Humboldt Fellow in Max-Planck-Institute of Solid State Research in Stuttgart, Germany, between 1994-1997, and a physicist and beamline scientist in Stanford University and Lawrence Berkeley National Lab between 1997-2006. He has developed a series of high resolution vacuum ultra-violet laser-based angle-resolved photoemission systems. His research focuses on studying electronic structure of high temperature superconductors, including cuprate superconductors and iron-based superconductors, and other quantum materials.
We have developed a near ambient pressure hard X-ray photoelectron spectroscopy (NAP-HAXPES) system at the BL36XU of SPring-8 and recently we have succeeded the XPS measurement under atmospheric pressure. Using this system, we observed the electrode reaction at the practical operation of the fuel cell under oxygen gas atmosphere. I will show the recent results of the AP-HAXPES measurement at BL36XU. In addition, I will also introduce other HAXPES measurement system of SPring-8 related to it.
Yasumasa Takagi received Ph.D. in Physics from the University of Tokyo in 2005. From 2005 to 2007, he was a postdoctoral researcher at RIKEN/SPring-8. From 2007 to 2017, he worked as an assistant professor at the Institute for Molecule science (Okazaki, Japan). From November 2017, he is a staff scientist at the Japan Synchrotron Radiation Research Institute (JASRI/SPring-8). His works are research and development of the hard x-ray photoelectron spectroscopy (HAXPES) measurement systems at SPring-8 beamlines. His research interests are in the application of the ambient pressure HAXPES and the depth-resolved HAXPES for investigating the liquid/solid and solid/solid interfaces.
One-dimensional (1D) electronic states are known to exhibit various interesting phenomena such as a breakdown of Fermi-liquid theory and density-wave formation. For practical applications, perfect suppression of backscattering related
to power-saving and high-speed conduction is predicted in 1D states with wavevector-dependent spin polarization such as Rashba effect or those of topological edge/surface states.
In this study, we have fabricated some quasi-1D surface atomic and electronic structures on anisotropic III-V semiconductor substrates. The surface electronic structures are revealed by angle-resolved photoelectron spectroscopy (ARPES) and spin-resolved APRES, showing quasi-1D dispersion with large spin-orbit splittings. Detailed quasi-1D spin texture as well as possible applications to spintronics would be discussed in the presentation.
Dr. Yoshiyuki Ohtsubo received his PhD at Kyoto University (Japan) in 2012 by a series of research about two-dimensional electronic structure on semiconductors. Afterward, he worked in synchrotron SOLEIL (France) as a post-doctoral researcher for 2 years to study the low-dimenisonal electronic structures of topological materials. Now, Dr. Ohtsubo is working at Osaka University (Japan) as an Assistant Professor to study 1D/quasi-1D surface electronic structures and topological electronic states in strongly-correlated electron systems. Most of his work is based on angle-resolved photoelectron spectroscopy (ARPES). He also uses spin-resolved ARPES and theoretical calculations to obtain further insight.
The electron states in transition-metal oxides are often driven into unconventional and nonequilibrium domains through electrochemical operations. Such unconventional states not only determine the practical parameters of the devices,
but also provide unique playgrounds for studying fundamental electronic structures with specific and atypical spin states, electron occupation, crystal fields, and excitations that could be triggered through soft X-ray spectroscopic
process. In this presentation, we will discuss recent soft X-ray findings of both the transition metals and oxygen states in energy storage (battery) materials. For transition metals, we show that soft X-ray absorption spectroscopy
could explain an intriguing interstitial water effect on electrochemical performance of transition metals with specific spin states, and full energy-range mapping of resonant inelastic X-ray scattering could clarify a century
long speculation of novel TM states in high-performance electrodes. For oxygen, we show that the inelastic scattering provides the ultimate probe of the intrinsic oxygen redox reactions in batteries, which is associated with
transition-metal configurations. The spectroscopic results provide both the rationality of the device performance and evidences for understanding the fundamental mechanism of electrochemical materials for energy applications.
 Wu et al., JACS 139, 18358 (2017)
 Firouzi et al., Nat Comm 9, 861 (2018)
 Gent et al., Nat Comm 8, 2091 (2017)
 Xu et al., Nat Comm 9, 947 (2018)
 Yang & Devereaux, J. Power Sources 389, 188 (2018)
Wanli Yang (杨万里) is a physicist staff scientist at Lawrence Berkeley National Laboratory. His research focus is on soft X-ray spectroscopy for studying materials for energy applications. He received his B.S. degree in physics from Shandong University, and Ph.D. degree from Institute of Physics, Chinese Academy of Sciences. He was a postdoc and then a staff scientist at Stanford University before working at Berkeley. He has led the efforts on the quantification of reaction mechanism in electrochemistry, and the development and understanding of full-energy range high-efficiency mapping of RIXS (mRIXS) of battery electrodes at the Advanced Light Source, through broad collaborations with material scientists and theoreticians.
Transition Metal Oxides (TMOs) exhibit unique and multifunctional physical phenomena (such as high-temperature superconductivity, colossal magnetoresistance, metal-insulator transitions, etc.) directly related to the spin and orbital
degrees of freedom of the transition metal d-states and their interplay with the lattice. Importantly, the iso-structure of TMOs permits realization of hetero-structures generating at their surfaces and interfaces new physical
matters that radically differ from those of the constituent bulk materials.
Through two examples, novel and fascinating properties emerged in TMO based hetero-structures and ways to control them will be presented:
1. Altering orbital ordering and band ﬁlling of the 2DEG at titanates surfaces. Employing ARPES we found ways to manipulate the 2DEG and, consequently, to tune electronic properties of titanates surfaces (SrTiO3 in bulk [1,2] and film forms, TiO2-anatase  and CaTiO3  films).
2. Tuning electronic phases in ultra-thin NdNiO3 (NNO) films via the strain and the proximity to the magnetic layer.
The electronic structure of differently strained NNO films grown solely and in proximity to magnetically ordered manganite layers has been studied. Our study reveals that substrate-induced strain tunes the crystal field splitting, consequently changing the FS properties, nesting conditions, and spin-fluctuation strength, and thereby controls the Metal Insulator Transition (MIT) . In addition, we found that the insulator anti-ferromagnetic (I-AF) ground state and MIT can be induced or quenched in ultra-thin NNO via the proximity to the magnetically ordered (AF or FM) manganite buffer layer .
Overall our studies establish different approaches to manipulate the properties of the two-dimensional electron gas and electronic phases in NNO signifying perspectives of TMO for novel applications.
 N. C. Plumb, M. Salluzzo, E. Razzoli, M. Månsson, M. Falub, J. Krempasky, C. E. Matt, J. Chang, J. Minár, J. Braun, H. Ebert, B. Delley, K.-J. Zhou, C. Monney, T. Schmitt, M. Shi, J. Mesot1, C. Quitmann, L. Patthey, M. Radović, Mixed dimensionality of confined conducting electrons in the surface region of SrTiO3, Phys. Rev. Lett. 113, 086801 (2014).
 Z. Wang, S. McKeown Walker, A. Tamai, Z. Ristic, F.Y. Bruno, A. de la Torre, S. Ricco, N.C. Plumb, M. Shi, P. Hlawenka, J. Sanchez-Barriga, A. Varykhalov, T.K. Kim, M. Hoesch, P.D.C. King, W. Meevasana, U. Diebold, J. Mesot, M. Radovic, and F. Baumberger, Tailoring the nature and strength of electron-phonon interactions in the SrTiO3(001) two-dimensional electron liquid", Nature Material 15, pages 835–839 (2016).
 Z. Wang, Z. Zhong, S. McKeown Walker, Z. Ristic, J.-Z. Ma, F. Y. Bruno, S. Riccò, G. Sangiovanni, G. Eres, N. C. Plumb, L. Patthey, M. Shi, J. Mesot, F. Baumberger and M. Radovic, Atomic scale lateral confinement of a two-dimensional electron liquid in anatase TiO2, Nano Letters 17 (4), pp 2561–2567 (2017).
 Stefan Muff, Mauro Fanciulli, Andrew P. Weber, Nicolas Pilet, Zoran Ristic, Zhiming Wang, Nicholas C. Plumb, Milan Radovic, J. Hugo Dil, Observation of a two-dimensional electron gas at CaTiO3 film surfaces, Applied Surface Science, Volume 432, 41-45 (2017).
 R. S. Dhaka, T. Das, N. C. Plumb, Z. Ristic, W. Kong, C. E. Matt, N. Xu, K. Dolui, E. Razzoli, M. Medarde, L. Patthey, M. Shi, M. Radovic, and J. Mesot, Tuning the metal-insulator transition in NdNiO3 heterostructures via Fermi surface instability and spin-fluctuations, Phys. Rev. B 92, 035127 (2015).
 Z. Ristic, R. S. Dhaka, T. Das, Z. Wang, C. E. Matt, N. C. Plumb, M. Naamneh, M. Shi, L. Patthey, M. Radovic, and J. Mesot, Quenching Insulator phase in ultra-thin NdNiO3 films via the proximity to the magnetic layer, under review in Phys. Rev. Lett. (2018).
Milan Radovic is staff scientist at Spectroscopy of Interfaces and Surfaces (SIS) Beam Line, Swiss Light Source at Paul Scherrer Institute, Switzerland. His research focusses on complex and artificial systems based on transition metal oxides with the aim of developing methods for tuning surface and interface electronic and magnetic properties. From 2016 Milan Radovic is appointed as Research Professor at University of Belgrade, Institute "Vinča", Serbia and from 2017 he is Adjucent Professor at Technical University of Denmark.
The growth of metal-surface oxides and its roles in surface reaction have been continuously investigated (and debated) as it reveals fundamental knowledge on how surface reaction takes place in the presence of oxides. Among many
of those studies, the surface oxides of Pt and Pd have been intensively studied and two different reaction mechanisms, i.e. Langmuir-Hinshelwood mechanism and Mars-van-Krevelen mechanism, have been employed to explain CO oxidation
reaction on both surfaces. [1-5] Recently, we revisited the study of CO oxidation on Pt(110) and Pd(100) using AP-XPS and RGA. When the surface temperature reaches the activation temperature for CO oxidation under oxygen rich condition,
the presence of surface oxides is observed on both surfaces. Interestingly, the gas phase of oxygen behaves differently from Pt surface to Pd surface under oxygen rich condition, reflecting opposite reaction properties of surface
oxides. The reaction properties of Pt and Pd surface oxides will be discussed.
 Hendriksen, B. L.; Frenken, J. W., Phys. Rev. Lett. 2002, 89, 046101.
 Lundgren, E.; Gustafson, J.; Mikkelsen, A.; Andersen, J. N.; Stierle, A.; Dosch, H.; Todorova, M.; Rogal, J.; Reuter, K.; Scheffler, Phys. Rev. Lett. 2004, 92, 046101.
 Toyoshima, R.; Yoshida, M.; Monya, Y.; Suzuki, K.; Mun, B. S.; Amemiya, K.; Mase, K.; Kondoh, H., J. Phys. Chem. Lett. 2012, 3, 3182-7.
 Butcher, D. R.; Grass, M. E.; Zeng, Z.; Aksoy, F.; Bluhm, H.; Li, W. X.; Mun, B. S.; Somorjai, G. A.; Liu, Z., J. Am. Chem. Soc. 2011, 133, 20319-25.
 Gao, F.; McClure, S. M.; Cai, Y.; Gath, K. K.; Wang, Y.; Chen, M. S.; Guo, Q. L.; Goodman, D. W., Surface Science 2009, 603, 65-70.
Bongjin Simon Mun is a professor at Gwangju Institute of Science and Technology, Korea. Upon receivinghis PhD in Physics at the University of California Davis in 2001, he worked at Advanced Light Source in Lawrence Berkeley National Laboratory as a beamline scientist. Since 2007, he moved to Korea and continued the surface science research using Ambient Pressure XPS and AR-PES. The main research goal of Mun is to identify the correlation between surface chemical properties and electronic structures under reaction conditions using various in situ operando science tools.
Now the sustainable development has become the word tendency. Nanoparticle catalyst has become more and more important to solve the energy or environment problems, such as hydrogen storage and purification exhaust gases (CxHy, CO,
NOx). Rh based alloy nanoparticles with effective cost, highly stability have exhibited excellent catalytic activity for hydrogen storage and NOx and CxHy reduction. However, the electronic origin of this kind of alloy nanoparticle
for the catalytic activity is still unclear. Firstly, we studied the lattice structure and electronic structure of Rh nanoparticle with different size to discovery the size effect. The smallest Rh NPs (~ 2 nm), had largest structural
disorder/increased vacancy spaces and the furthest edge from the Fermi level, and so exhibited hydrogen-storage capacity. Then, to lower the application cost, Ag or Cu elements were alloyed into Rh nanoparticle. The valence
band (VB) structures of face-centered-cubic Rh-Ag alloy nanoparticles are not a simple linear combination of the Ag VB spectrum and Rh VB spectrum. The electronic features of the Rh-Ag alloy near the Fermi edge was strikingly similar
to that of well-known Pd nanoparticles for hydrogen storage. The core level and valence band of Rh-Cu alloy nanoparticles confirmed the intermetallic charge transfer occurs between Rh and Cu. The decreased fraction of catalytically
active Rh(3-δ)+ oxide is compensated by charge transfer. As a result, ensuring negligible change in the catalytic activities of the NPs with comparable Rh:Cu ratio to those of Rh-rich and monometallic Rh NPs.
1. C. Song, A. Yang, O. Sakata, L. S. R. Kumara, S. Hiroi, Y.-T. Cui, K. Kusada, H. Kobayashi and H. Kitagawa, Phys. Chem. Chem. Phys. DOI: 10.1039/C8CP01678J (2018)
2. A. Yang, O. Sakata, K. Kusada, T. Yayama, H. Yoshikawa, T. Ishimoto, M. Koyama, H. Kobayashi, and H. Kitagawa, Appl. Phys. Lett. 105 (2014), 153109.
3. N. Palina, O. Sakata, L. S. R. Kumara, C. Song, K. Sato, K. Nagaoka, T. Komatsu, H. Kobayashi, K. Kusada, and H. Kitagawa, Sci. Rep. 7 (2017), 41264.
Osami Sakata received the Ph.D. degree in materials science from the Tokyo Institute of Technology, Japan in 1994. He had studied his extended dynamical X-ray diffraction for such crystals using synchrotron X-ray experiments performed at the Photon Factory until 1998. He researched on crystal surfaces at Northwestern University, Evanston, IL, USA and Advanced Photon Source, Argonne, IL, USA, from 1998 to 2000. His research place moved to the SPring-8 in 2000. He was involved in construction of the beamline BL13XU for surface and interface structures at the Japan Synchrotron Radiation Research Institute and studied atomic structures of semiconductors and metals as well as functional oxide thin films. He joined the National Institute for Materials Science in 2011. His current research interests include atomic-scale structures and electronic states of functional nanoparticles and thin films. He is the Station Director of the Synchrotron X-ray Station at SPring-8, the group leader of the Synchrotron X-ray group, and an Adjunct Professor at the Tokyo Institute of Technology. He has 238 original publications including an article from Nature Chemistry and Science, respectively, and two from Nature Materials as well as a patent. He gave 55 invited talks and wrote 10 chapters (including two written in English) in books with co-authors.
We will present several new directions in the use of both soft- and hard- x-ray photoemission for the study of bulk materials, buried interfaces and atomic layers. In particular, we will consider using standing-waves (SWs) produced
by Bragg reflection from multilayer heterostructures of metal oxides to provide information on interfacial bonding  and momentum-resolved electronic structure , for the case of La0.67Sr0.33MnO/SrTiO3; the spatial extent of
a 2D electron gas, for GdTiO3/SrTiO3 ; and the detailed built-in potential for a system with polar interfaces, LaCrO3/SrTiO3 . The concentration profiles at the liquid-solid interface between Fe2O3 and a solution of CsOH
and NaOH has also been determined .
Also with multilayer heterostructure SW production, we will show that it is possible to give resonant inelastic x-ray scattering (RIXS) depth sensitivity, e.g. to excitations at buried interfaces, for the system of superconductor La1.85Sr0.15CuO4 and half-metallic ferromagnet La0.67Sr0.33MnO3 .
We will also discuss SW photoemission based on Bragg reflection from single-crystal epitaxial atomic planes. We will show that it is possible to use SW hard x-ray ARPES (HARPES) to probe element- and momentum- resolved electronic structure, for GaAs and the Mn-doped dilute magnetic semiconductor (Ga,Mn)As . Finally, we will show that, for the high-TC superconductor Bi2Sr2CaCu2O8+δ, soft SW x-ray photoemission has permitted determining the atomic-layer resolved composition and valence-electron densities of states for the first time .
Davis authors were supported by the U.S. Department of Energy under Contract No. DE-SC0014697.
 “Interface properties of magnetic tunnel junction La0.7 Sr0.3 MnO3/SrTiO3 superlattices studied by standing-wave excited photoemission spectroscopy”, A. X. Gray et al., Phys. Rev. B 82, 205116 (2010).
 “Momentum-resolved electronic structure at a buried interface from soft X-ray standing-wave angle-resolved photoemission”, A. X. Gray et al., Europhysics Letters 104, 17004 (2013).
 “Energetic, spatial, and momentum character of the electronic structure at a buried interface: The two dimensional electron gas between two metal oxides”, S. Nemšák et al., Phys. Rev. B 93, 245103 (2016).
 “Interface properties and built-in potential profile of a LaCrO3/SrTiO3 superlattice determined by standing-wave excited photoemission spectroscopy”, S.-C. Lin et al., to be published, https://arxiv.org/abs/1802.10177.
 “Chemical-state resolved concentration profiles with sub-nm accuracy at solid/gas and solid/liquid interfaces from standing-wave ambient-pressure photoemission”, S. Nemšák et al., Nature Communications 5, 5441 (2014).
 “Depth-resolved resonant inelastic x-ray scattering at a superconductor/half-metallic ferromagnet interface through standing-wave excitation”, C.-Tai Kuo et al., to be published
 “Hard x-ray standing-wave angle-resolved photoemission: element- and momentum-resolved band structure for a dilute magnetic semiconductor”, S. Nemšák et al., submitted to Nature Communications, https://arxiv.org/abs/1801.06587.
 "Atomic-layer resolved electronic structure of the high-temperature superconductor Bi2Sr2CaCu2O8 from standing-wave soft x-ray angle-resolved photoemission", C.-T. Kuo et al., to be published, http://arxiv.org/abs/1801.05142.
Charles (Chuck) Fadley: S.B. MIT, M.S. and PhD Berkeley, presently Distinguished Professor of Physics at UC Davis and Senior Faculty Scientist, Materials Sciences, LBNL. An internationally recognized pioneer and continuing innovator in photoelectron spectroscopy (photoemission) for the study of the atomic and electronic structure of solid materials, their surfaces, and the interfaces between them. His key developments include angle-resolved x-ray photoelectron spectroscopy for surface analysis, photoelectron diffraction for atomic structure determination, higher-energy more bulk sensitive angle-resolved band-structure studies, and most recently standing-wave and hard x-ray photoemission for buried interface and bulk materials studies. These techniques have been applied to oxidation, epitaxial growth, semiconductors, magnetic materials and nanostructures, strongly correlated oxides, quasi 2D quantum materials, and liquid-solid interfaces, with significant relevance to pure and applied physics, chemistry, and materials science. Synchrotron radiation is a key element of his experimental work. He has received various honors, including the AVS Welch Award, a Humboldt-Helmholtz Prize, an Uppsala honorary doctorate, the ALS Shirley Award, a visiting professorship at Soleil/University of Paris, and a Sloan Fellowship. He is an elected Fellow of the AVS, APS, Institute of Physics, AAAS, Surface Science Society of Japan, and Elettra. He has attended all but one of the ICESS Conferences, Co-Chairing one, being Chair of the International Advisory Board for another, and being a member of the Organizing and Program Committees for several others.
Magnetic ordering is a ubiquitous ingredient in the phase diagram of a Mott insulator, and the magnetic interaction is at the heart of determining the electronic behaviors in materials. In this talk, I will describe how X-ray measurements can be employed to study the evolution of the magnetism in the iridates upon laser-photo-doping. With time-resolved resonant elastic X-ray magnetic scattering (REMS) and inelastic X-ray scattering (RIXS), both the long range order and the dynamics of the magnetism were studied in Sr2IrO4 and Sr3Ir2O7 in various time scales. Our results show multi-stage ultra-fast recovery, and the existence of meta-stable spin states.
We review spectroscopic-imaging STM studies on bulk Fe(Se,S) in which superconductivity and nematicity coexist. We show that superconductivity is strongly affected by the presence or absence of nematicity. FeSe is also known as a superconductor in the BCS-BEC crossover regime. We show that pseudo-gap above Tc, which is expected in this regime, is absent because of the multi-band nature.
Tetsuo Hanaguri is a team leader at RIKEN Center for Emergent Matter Science. He obtained his PhD from Tohoku University in 1993. He worked as a research associate and an associate professor at the University of Tokyo before moving to RIKEN in 2004. He has been working in the field of low-temperature experiments and has transferred about 30,000 litters of liquid helium to the cryostats during his career. He is currently interested in spectroscopic-imaging scanning tunneling microscopy on unconventional superconductors and topological materials.
Half-metallic materials are very interesting systems for spintronic devices where fully spin polarized currents and high spin filtering effects is required. The characterization of the bulk properties by photoemission remains very
challenging due to surface reconstruction . Here we propose a novel approach to investigate the bulk half-metallicity in a material by monitoring the electron spin dynamics above the Fermi level after photoexcitation. In order
to model the electron thermalization, we numerically solve the time-dependent Boltzmann equation for the archetype half-metal Fe3O4 excited by femtosecond laser pulse. On short time scale, the electron thermalization leads to identical
electronic temperature in both spin channels but with three different chemical potentials. At the bottom of the conduction band, in the gaped spin channel, electrons have a longer life time governing the hot carrier spin polarization.
Experimentally we performed time- and spin- resolved photoemission measurements in the vicinity of the Fermi level using 4.65 eV photon energy. Interestingly the spin polarization above the Fermi level increases over the first
picosecond delay. We attribute this effect to the bulk – surface dynamics as previously observed in different systems . The long lasting out-of-equilibrium distribution in the conduction band lead to an increase of the spin
polarization well above EF despite the metallic nature of the surface. This peculiar spin dynamics  is attributed to the bulk half metallicity of the material.
 Wang et al., PRB 87, 085118 (2013)
 Cacho et al., PRL 114, 097401, (2015)
 Battiato et al., arXiv:1802.10356, (2018)
Céphise Cacho obtained his PhD at the Ecole Polytechnique (Paris) investigating the spin-dependent transmission of ballistic electrons through freestanding ferromagnetic thin films. Early 2000, he joined the Synchrotron Radiation Source at Daresbury (UK) to lead the development of a unique instrument (ToF-spin analyser) to carryout spin-resolved photoemission efficiently. In the frame of a collaboration between STFC (UK) and Elettra, he then jointed the Fermi@Elettra (Italy) team to perform time-and spin-resolved photoemission on novel materials with high spin-orbit coupling. In 2010, he returned to the Central Laser Facility (UK) to lead the time-resolved ARPES user activity with HHG source investigating novel materials such as graphene, TMDC materials and Topological Insulator. In 2018, Céphise joint Diamond Light Source as Principal Beamline Scientist to manage the ARPES beamline I05 that offer High Resolution ARPES and Nano-ARPES to the user community. His main scientific interest are related to strongly correlated material and quantum materials such as superconductor, TMDC, Graphene, Topological materials, Dirac and Weyl semimetal.
Complex aqueous solutions with ions widely exist. Similarly, this world is rich of carbon-based materials; most of them contain many aromatic rings structures, which are hexagonal carbon rings rich in π electrons. Early in 1980’s,
the interactions of the aromatic rings with ions were proposed, namely ion-π interactions. The ion-π interactions are greatly reduced by the hydration of ions and thus the ion-π interactions of ions in solutions have been usually
neglected. In this talk, I will show that, due to the multi ions in the solutions and the polycyclic aromatic rings structure which includes more π electrons, the hydrated ion-π interactions play important roles in the systems
with aqueous ions solutions and carbon-based materials. The using of Electron Spectroscopy in the characterization is emphasized. <1> Aromatic ring is the most important hydrophobic group in biological systems. Consequently,
aromatic amino acids and peptides have a very low solubility in water and aqueous solutions. We will show that there is an unexpectedly high solubility of the aromatic acids and peptides in aqueous solution of divalent transition-metal
cations . The key to this observation is the hydrated cation-π interactions between the hydrated cation and the aromatic rings. <2> It has long been expected that the CNT can be used as an excellent seawater desalination
membrane because of its experimentally confirmed ultrafast pure water flow and theoretically predicted ion rejection. However, there is insufficient experimental evidence of adequate salt rejection for desalination before 2015.
We explain this difficulty by showing the blockage of CNTs by hydrated cations because of the hydrated cation-π interactions of cations in solutions with aromatic rings in CNTs . <3> We proposed based on hydrated cation-π
interaction and experimentally demonstrate the cationic control of interlayer spacing of GO membranes with precision as small as 1 Å using ions themselves . <4> NaCl in 1:1 stoichiometry is the single known stable form
of the Na–Cl crystal under ambient conditions. We report the direct observation, under ambient conditions, of Na2Cl and Na3Cl as two-dimensional Na–Cl crystals on reduced graphene oxide membranes and on the surfaces of natural
graphite powders from salt solutions far below the saturated concentration . This unconventional crystallization originates from the cation–π interaction. With unique electron and spin distributions and bonding, the resulting
2D crystals may have unusual electronic, magnetic, optical and mechanical properties.
 Guosheng Shi, et al., Phys. Rev. Lett. 117, 2381021(2016).
 Jian Liu, et al., Phys. Rev. Lett. 115, 164502 (2015).
 Liang Chen, et al., Nature 550, 380 (2017).
 Guosheng Shi, et al., Nature Chem., 10,776(2018)
Haiping FANG is a Senior Research Scientist and Director of the Division of Interfacial Water at the Shanghai Institute of Applied Physics, Chinese Academy of Sciences. He received his Ph.D. in theoretical physics from the Institute of Theoretical Physics, Chinese Academy of Sciences in 1994. His current research interests include the behavior of statistical physics at the nanoscale, interfacial water and its biological significance, the behavior of hydrated-ion confined on biological and other carbon-based surfaces, and dynamics of nanobubbles and nanobubble-protein interactions. He has more than 150 journal publications include Nature, Nature Nanotechnology, Nature Chemistry, PNAS and PRL, and 6 patents. He won the 100 Talents Program of the Chinese Academy of Sciences in 2002, National Science Fund for Distinguished Young Scholars in 2008, and Shanghai Leading Academic Discipline Project in 2009.
Since 2015, the free-electron lasers (FELs) as a new generation of advanced radiation sources, has been becoming an extremely powerful research platform for experimental studies of light-matter interactions in unexplored conditions.
In atomic, molecular and optical (AMO) physics, short-wavelength FELs illuminate outstanding applica-tions for exploring multi-photon nonlinear phenom-ena, observing and controlling reaction dynamics of electrons, atoms and molecules.
Experimental studies from simple helium atom to complex bio-molecules, outer-shell to inner-shell electrons, sin-gle-photon to multi-photon processes, pulse exper-iments to time-resolved pump-probe approaches, extreme ultraviolet
to hard X-ray regimes, energy spectra to time-resolved momentum spectra have successfully achieved.
Shanghai X-ray FELs delivering seeded and SASE radiations with wavelengths of 50-500 eV and 500-1500 eV, repetition rates of 10-50 Hz, pulse energies of a few µJ to 200 µJ were granted. User endstations will cover applications for AMO, chemical reactions, surface science and biomole-cules. For AMO endstation, it will be mounted into the seeded SXFEL beamline, where a combined Coltrims and VMI imaging technologies are planned. More details will be given in the presentation. Finally, our new apparatus, so called Rb Mo-trims, is introduced and preliminary results will be discussed.
The work is supported by National Natural Science Foundation of China (11420101003, 61675213, 11604347, 91636105)
Prof. Yuhai Jiang received his PhD in atomic and molecular physics in Free University Berlin in 2006 and then worked in MPIK Heidelberg till 2011. Nominated as “100 talents program” of CAS and “Pujiang talents”. He started a full professor position in Shanghai Advanced Research Institute of CAS in 2012. He is also joint professor of CAS university and ShanghaiTech university. His research interests are engaged in experimental and theoretical studies on atomic and molecular physics in the strong laser field, supported by Chinese national foundation projects of free electron laser beamline constructions, NSFC international key cooperation, NSFC major apparatus development, CAS apparatus development etc.
Majorana zero modes (MZM) are a key component for realizing topological quantum computing. MZMs are predicted to exist at the ends of a 1D nanowire coupled to a superconductor, or in the vortex core of a topological superconductor, which can be detected as a zero-bias conductance peak (ZBCP) in tunneling spectroscopy. However, in practice clean and robust MZMs have not been realized in the vortices of a superconductor, due to contamination from impurity states or oth-er closely-packed Caroli-de Gennes-Matricon (CdGM) states, which hampers further manipulations of MZMs. Here using scanning tunneling spectroscopy, we show that a ZBCP well separated from the other discrete CdGM states exists ubiquitously in the cores of free vortices in the defect free regions of (Li0.84Fe0.16)OHFeSe, which has a superconducting transition temperature of 42 K. Moreover, a Dirac-cone-type surface state is observed by angle-resolved photoemission spectros-copy, and its topological nature is confirmed by band calculations. The observed ZBCP can be natu-rally attributed to a MZM arising from this chiral topological surface states of a bulk superconductor. (Li0.84Fe0.16)OHFeSe thus provides an ideal platform for studying MZMs and topological quantum computing.
Tong Zhang is a professor at department of physics, Fudan University. He received his Ph.D at pnstitute of physics, Chinese academy of science in 2010. His research field is low temperature STM and his research interests include correlated systems, unconventional superconductors, charge/spin/orbital ordered systems and topological materials. He has published 40 papers in peer-reviewed journals include Nature Physics, PRL, Nature Communications, Nano letters and had been cited for over 3000 times.
The uranium compounds URu2Si2 and USb2 present fascinating low temperature phase diagrams, and are focal points of long-standing debates regarding how the crossover between strong correlations and electronic itinerancy should be conceptualized and evaluated. It has recently been found that uranium O-edge resonant X-ray spectroscopies can help to image this multi-natured wavefunction by providing a fingerprint of the f-electron atomic multiplet states. I will present a systematic O-edge spectroscopic characterization of URu2Si2 and USb2 as a function of doping, and show that these data align well with a Hund’s metal picture for both compounds. Distinct differences in the degree of “Hundess” (same-atom alignment of electron magnetic moments) as a function of chemical composition are found to underlie important features of the low temperature phase diagrams, such as the transition from a hidden order phase to antiferromagnetism, and the loss of a low temperature coherence feature in transport measurements. Based on these results, I will propose that developing the RIXS technique to achieve a more quantitative experimental characterization of Hundness in many-body wavefunctions is of fundamental importance to the broader goal of understanding the phase diagrams in metallic systems with non-trivial local moment physics.
L. Andrew Wray is an Assistant Professor of Physics at New York University, and a member of the NYU-ECNU Joint Physics Research Institute. Wray’s research focuses on the discovery, characterization and manipulation of novel quantum states inside materials. His experiments have been instrumental in identifying the first realizations of topologically ordered quantum states of matter such as the topological insulator and topological superconductor. Incisive in-situ investigation of the energy and momentum profiles of quantum states is made possible by rapidly advancing capabilities at state of the art X-ray facilities. Wray maintains active involvement in proposing new X-ray science technologies and developing novel methods to simulate and analyze resonant interactions between X-rays and matter.
I21 is a dedicated Resonant Inelastic soft X-ray Scattering (RIXS) beamline that provides a highly monochroma-tised, focused and tunable X-ray beam onto materials, while detecting and energy-analysing scattered X-rays using variable-line spaced grating-based beamline and spectrometer and a spatially-resolved two-dimensional detector. Exploiting the ultra-high energy resolution of RIXS, I21 is suited to investigate the electronic, magnetic and lattice dynamics of samples particularly those with magnetic and electronic interactions offering new perspectives for condensed matter physics. I21 beamline covers an energy range from 250 to 3000 eV with a designed combined energy resolution of 35 meV at 1 keV. To achieve such demanding goal, we constructed a 81 meter long beamline with a 15 meter long RIXS spectrometer which can pivot around the sample continuously by 150 degrees. Through the x-ray commissioning, we have obtained the energy resolution of about 35 meV at Cu L-edge (930 eV) and about 15 meV at Oxygen K-edge (532 eV). In this talk, I will briefly present the I21 RIXS facility with key technical achievements. In the 2nd part of the presentation, I will talk about our recent RIXS work focusing on the charge order and the electron-phonon couplings of the single-layer Bi2Sr2-xLaxCu2O6+δ superconductor.
Dr. Ke-Jin Zhou is the Principal Beamline Scientist of the I21 Resonant Inelastic soft X-ray Scattering (RIXS) beamline in Diamond Light Source in the United Kingdom. He obtained his B.S. in Nanjing Normal University in 2002 and
his M.S. and Ph.D degrees in the Institute of High Energy Physics (IHEP), Chinese Academy of Sciences in 2014 and 2007 respectively. His PhD thesis titled as the RIXS application on to strongly correlated electronic systems was
the first realisation of RIXS technique in Chinese synchrotron facilities.
From October 2007 to October 2008, Dr. Zhou carried out his postdoctoral research in University Pierre and Marie Curie, France. And from October 2008 to April 2012, Dr. Zhou was a research fellow at Swiss Light Source, Paul Scherrer Institut, Switzerland. In 2012, Dr. Ke-Jin Zhou took upon the post of Principal Beamline Scientist at Diamond Light Source, UK, for the Beamline project of the ultra-high energy resolution RIXS. The Beamline project was launched in April 2012 and the construction was completed by summer 2017. In September 2017 the RIXS beamline (I21-RIXS) received the first users very successfully for being as one of world leading RIXS facilities.
His scientific focus is at the core of strongly correlated electronic systems including unconventional high Tc superconductors (copper oxides and iron-based superconductors), artificial oxide heterostructures, as well as low-dimensional quantum materials using ultra-high energy resolution RIXS.
More often than not, interfaces of two materials give rise to a new set of properties distinctively different from the bulk counterparts. Thanks to practically limitless combination of materials, interface engineering provides a
vast playground for exploring new phenomena. Experimental techniques capable of extracting electronic information from buried interfaces are thus crucial in providing a valuable feedback for the material synthesis and as such they
have to deliver certain specific information (electron energy, momentum, spin). On top of that, they have to be highly depth selective in order to distinguish interface and bulk properties. Standing-wave X-ray photoelectron spectroscopy
(SW-XPS) is one of the few non-destructive techniques fulfilling all these requirements. SW-XPS makes use of a Bragg-reflection from the standing-wave generator, with the modulation of the standing wave providing a highly selective
probe of depth.
This technique have been successfully implemented to study emergent phenomena at complex oxide interfaces such as GdTiO3/SrTiO3 (2D electron gas depth distribution in SrTiO3) and LaNiO3/SrTiO3 (interfacial band gap opening in LaNiO3). Just recently, standing wave hard X-ray photoemission was also used to obtain site- and element- specific band structure of the single crystal magnetic diluted semiconductor. In another example, the superb depth selectivity and chemical sensitivity of standing wave ambient pressure photoelectron spectroscopy is exploited to probe two different solid/liquid interfaces relevant to energy research, electrochemistry, and atmospheric and environmental science. The study of ionic adsorption at the hematite/liquid interface was performed in soft X-ray regime and a corrosion study of nickel, with substantially larger liquid film thickness, used tender X-rays.
S. Nemsak et al., Physical Review B 93(24), 245103 (2016)
D. Eiteneer et al., Journal of Electron Spectroscopy and Related Phenomena 211, 70-81 (2016)
S. Nemsak et al., Nature Communications 9, 3306 (2018)
S. Nemsak et al., Nature Communications 5, 5441 (2014)
O. Karlsioglu et al., Faraday Discussions 180 (2015)
Slavomir Nemsak is a staff scientist at the Advanced Light Source, Lawrence Berkeley National Laboratory, USA, where he is responsible for ambient pressure photoemission end-station of the beamlines 9.3.2 and 9.3.1. His previous appointment was at BESSY-II, Berlin, Germany managing the photoemission microscopy group. His scientific interests involve further development of X-ray standing-wave photoemission spectroscopy and microscopy and their application to the materials relevant for next generation electronics and energy materials.
Photon-based spectroscopies provide an efficient approach to investigate the microscopic physics of materials and have had a significant impact on both fundamental sciences and technological applications. Together with the development of synchrotron X-ray techniques, theoretical understanding of the spectroscopies themselves and the underlying physics that they reveal has progressed through advances in numerical methods and scientific computing. In this talk, I will provide an overview of theories for photoemission and X-ray scattering applied to quantum materials and discuss the recent development of ultrafast techniques for out-of-equilibrium spectroscopies, mainly from a theoretical point of view.
Professor Devereaux is currently the Director of the Stanford Institute for Materials and Energy Sciences (SIMES), a professor in the Photon Science Faculty at SLAC National Accelerator Laboratory and Stanford University and a Senior Fellow of the Precourt Institute for Energy. His main research interests lie in the areas of theoretical condensed matter physics and computational physics. His research effort focuses on using the tools of computational physics to understand quantum materials. The goal of his research is to understand electron dynamics via a combination of analytical theory and numerical simulations to provide insight into materials of relevance to energy science.
Electron momentum spectroscopy is a well-developed technique for investigating the electronic structures of atoms and molecules. The unique ability of directly “imaging” the electron momentum distributions for individual molecular orbitals, especially the chemical important valence orbitals, provides straightforward information for understanding chemical properties and reactivity. However, further application of EMS has largely been limited by its low coincidence count rate and poor energy resolution (typically 1~2 eV). Up to date, most of the EMS applications are restricted to the valence orbitals of atoms and randomly oriented small molecules in ground state. Meanwhile, the molecular geometry information is usually veiled due to the single-centered character of momentum space wavefunction of molecular orbital. In this talk, I will introduce our recent work on the development of a new high-sensitivity electron momentum spectrometer for time-resolved experiments in nanosecond timescale. I will also report our effort in retrieval of interatomic distances from the interference effect revealed in the electron momentum profiles of molecules.
Dr. Xiangjun Chen is a professor of Department of Modern Physics, University of Science and Technology of China (USTC) and a principal investigator in Hefei National Laboratory for Physical Sciences at the Microscale. He received his B.S and Ph.D degrees from USTC. His research interest mainly focuses on electron impact ionization and dissociation of molecules, as well as scanning probe electron spectroscopy on surface. He published more than 100 peer-reviewed journal papers including Nature Physics, Phys. Lett., Phys. Rev. A.
Stanene and its derivatives can be 2D topological insulators (TI) with a very large band gap as proposed by first-principles calculations, or can support enhanced thermoelectric performance, topological superconductivity and the near-room-temperature quantum anomalous Hall (QAH) effect. For the first time, we report a successful fabrication of 2D stanene by MBE. The atomic and electronic structures determined by STM and ARPES agree well with the predictions by first-principles calculations. This work will stimulate the experimental study and exploring the future application of stanene. In the second part of the talk, I will talk about the Landau levels induced by pseudo-magnetic field in strained. Topological crystalline insulators (TCI) are a class of new quantum phases with their non-trivial topology arisen from crystalline symmetries. One of unique properties of TCIs is the highly tunability under external strain, which can break the crystalline symmetries and hence manipulate the nontrivial topological boundary states. Typically, strain can be used to realize many novel phenomena, such as the mass generation at Dirac points, as well as topological phase transitions. Here, by mean of molecular beam epitaxy, we successfully grow SnTe thin films on SrTiO3 substrate to fabricate a strained TCI system. Interestingly, pseudo Landau quantization is observed in this system for the first time, induced by a strong uniaxial strain with inhomogeneity. The extracted pseudo magnetic field is estimated to over 100 Tesla, which is the highest record ever reported in the family of the Dirac-cone like linear dispersed surface states materials. Our findings may support the newly developed research field of ‘strain engineering’.
Dr. Jinfeng Jia graduated from Peking University in 1987. He received his Ph.D in condensed matter physics from the same university in 1992. From 1995 to 1996, he worked as a JSPS post-doc at Institute for Materials Research, Tohoku University, Japan. From 1996 to 2001, he worked as an associated professor at Department of Physics, Peking University. During the time, he worked as a visiting scientist in USA for 3 years. In 2001, he received the “100 Talents Project” of Chinese Academy of Sciences (CAS) and became a professor at Institute of Physics, CAS. From 2006 to 2009, he worked as a professor at Department of Physics, Tsinghua University. In 2009, he became a Cheung Kong Professor at Dept. of Physics, Shanghai Jiaotong University. Prof. Jia’s main research interests include topological superconductors and new quantum materials, quantum phenomenon in low-dimensional nano-structures, thin film growth by molecular beam epitaxy. He authored more than 250 papers, including 4 in Science, 3 in Nature Phys., 2 in Nature Mater., 5 in Adv. Mater., 21 in Physical Review Letters. He received a number of recognitions, including the Scientific and Technological Progress Award of Chinese State Education Commission (first class, 1997), Chinese National Natural Science Funds for Distinguished Young Scholar (2003), Prize for Advancement in Science and Technology of Beijing (first class, 2003), National Prize for Advancement in Natural Science (second class, 2004), Outstanding Science and Technology Achievement Prize of CAS (2005), National Prize for Advancement in Natural Science (second class, 2011), Group Award for Outstanding Science and Technology Achievement from Qiu Shi Science & Technologies Foundation of Hong Kong, 2011 and Achievement in Asia Award (AAA) (Robert T. Poe Prize) by the International Organization of Chinese Physicists and Astronomers (OCPA, 2013), Prize for Advancement in Natural Science of Chinese Ministry of Education (First class, 2016) and the Special Prize for Advancement in Natural Science of Chinese Ministry of Education (2017).
Traditional photoemission spectroscopy and electron microscopy methods including XPS and PEEM are based on ultrahigh vacuum conditions. Near ambient pressure (NAP) XPS and NAP-PEEM have been developed and built in our lab in order
to investigate surface and interface pro-cesses in energy and catalysis close to the real reaction conditions. Two-dimensional (2D) nanore-actor formed under 2D materials can provide a well-defined model system to explore confined
ca-talysis and energy processes using the NAP surface science techniques. For one aspect, we demon-strate a general tendency for weakened surface adsorption under 2D overlayer, illustrating the fea-sible modulation of surface reactions
by placing a 2D cover. The confinement effect of the 2D cover leads to new chemistry in a small space, such as “catalysis under cover” and “electrochemis-try under cover”. Furthermore, the interlayer within 2D materials provides
2D space for ion diffu-sion and intercalation, which is the fundamental step of the secondary ion batteries. Here, Al-ion battery processes under the 2D materials have been dynamically visualized by operando-XPS an the charging
mechanism has been revealed.
 Mengmeng Sun, Jinchao Dong, Yang Lv, Siqin Zhao, Caixia Meng, Yujiang Song, Guoxiong Wang, Jianfeng Li*, Qiang Fu*, Zhongqun Tian, Xinhe Bao, “Pt@h-BN core-shell fuel cell electrocatalysts with electrocatalysis con-fined under outer shells”, Nano Research, 2018, 11, 3490-3498;
 Haobo Li, Jianping Xiao, Qiang Fu*, Xinhe Bao, “Confined catalysis under two-dimensional materials”, PNAS, 2017, 114 (23), 5930-5934;
 Qiang Fu*, Xinhe Bao, “Surface chemistry and catalysis under two-dimensional materials”, Chemical Society Review, 2017, 46, 1842-1874;
Qiang Fu obtained his B.S. in 1996 from Beijing Institute of Technology and his Ph.D. in 2000 from the same university. Subsequently, he joined Max Planck Institute for Metal Research in Stuttgart for his postdoc-toral studies. In 2005, he moved to Fritz Haber Institute of the Max Planck Society. In 2006, he took a posi-tion in Dalian Institute of Chemical Physics CAS and became a full professor in 2008. He is leading a group working on surface and interface catalysis. His main research interest includes surface catalysis on oxides and two-dimensional materials, confined catalysis at interfaces, and development of new surface characterization techniques.
A class of QSH materials were predicted in the single-layer 1T’-phase of transition metal dichalcogenide (TMD), TX2, where T represents a transition metal atom (Mo, W) and X stands for a chalcogen atom (S, Se or Te). The band inversion happens between transition metal d orbitals and chalcogenide p orbitals, and the SOC interaction further opens a fundamental band gap. Recently, many experiments confirmed multiple topological states in 1T'-phase of TMD materials. For example, high-temperature QSH effect were recently reported in the single-layer 1T' WTe2; Type-II Weyl semimetal were confirmed in bulk 1T' MoTe2. In this talk, I will review some progress of topological states in these TMD materials, especially the work focused on by our group, such as, type-II Weyl semimetals, quantum spin Hall state and topological insulators.
Dr. Haijun Zhang is a professor of College of Physics of Nanjing University and National Laboratory of Solid State Microstructures. His scientific interest is on all kinds of novel physical properties in condensed matter physics
and their potential applications, such as, topological quantum states, two-dimensional (2D) materials and so on. He has published more than 40 scientific articles, and the total citation is more than 13,750 (from google citation).
Jiangsu Innovation and entrepreneurial talent program，2016
Thousand Youth Talents PlanProject of Thousand Youth Talents, 2015
Outstanding Science and Technology Team Achievement Award, Qiu Shi Science & Technologies Foundation, 2011
Outstanding Achievement Award in Science and Technology, Chinese Academy of Sciences, 2011
Education and experience:
Jan. 2015-now Professor, College of Physics, Nanjing University
Mar. 2010-2015 Postdoctoral scholar, Geballe Laboratory for Advanced Materials(GLAM), Stanford University, Stanford, CA, 94305, USA
Sep. 2004-Oct. 2009 Ph. D from Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics(IOP), Chinese Academy of Sciences (CAS), Beijing, China
Sep. 2000-July 2004 Bachelor from Department of Physics, University of Science and Technology of China (USTC), Hefei, Anhui, China
Dr. Shen is the Paul Pigott Professor in Physical Sciences, a senior fellow of the Precourt Institute for Energy, and a member of the faculty advisory board for the Knight-Hennessy Scholars Program at Stanford University. He is a Member of the National Academy of Sciences and a fellow of American Academy of Arts and Sciences. He is an expert on quantum phenomena in materials, and a recipient of E.O. Lawrence Award of the Department of Energy, the Oliver E. Buckley Prize of the American Physical Society, the Kamerlingh Onnes International Prize on Superconductivity, and the Einstein Professorship Award of the Chinese Academy of Sciences. He served as the Chief Scientist of SLAC National Accelerator Laboratory, the Director of the Geballe Laboratory for Advanced Materials, and the Director of the Stanford Institute for Materials and Energy Sciences. He mentored about 80 graduate students and postdoctoral fellows, and co-founded three companies.