Description
chairman: T. Schmitt, D.-J.Huang, U.Staub, J.van den Brink
Dr
Thorsten Schmitt
(Paul Scherrer Institut),
Urs Staub
(Paul Scherrer Institut)
9/16/11, 9:00โฏAM
Thomas P Devereaux
(Stanford University)
9/16/11, 9:10โฏAM
Resonant Inelastic and Elastix X-ray Scattering
Talk
In this talk I will present an efficient scheme for calculating various x-ray spectroscopies using a combination of cluster exact diagonalization and ab-initio codes. These multi-orbital calculations include multiplet, charge-transfer, hybridization, and core-hole interactions all on the same footing, and are able to reproduce fairly well representative spectra on several transition metal...
Dr
V Scagnoli
(Swiss Light Source, Paul Scherrer Institut, CH 5232 Villigen PSI, Switzerland)
9/16/11, 9:40โฏAM
Resonant Inelastic and Elastix X-ray Scattering
Talk
Cupric oxide (CuO) has recently attracted much interest as a magnetically driven multiferroic with the highest Tc (~230K). In this material a non-collinear spiral magnetic order (215K<T<230K) breaks crystal inversion symmetry, inducing ferroelectricity. We use resonant x-ray diffraction at the Cu L edges to probe the subtle changes in the Cu electronic structure occurring at the appearance of...
Dr
C H Du
(Department of Physics, Tamkang University, Tamsui 251, Taiwan)
9/16/11, 10:10โฏAM
Resonant Inelastic and Elastix X-ray Scattering
Talk
Using resonant x-ray scattering, we report the study of electronic structures in the ion-based oxides SrFeO3-ฮด. SrFeO3 (SFO) has a cubic structure with an isotropic metallic behavior. The cubic perovskite SrFeO3, in which iron is present as Fe4+, exhibits the coexistence of metallic conductivity and screw-type antiferromagnetic ordering. However, the metallic state found in SrFeO3 becomes...
C Schueรler-Langeheine
(Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin fรผr Materialien und Energie, Germany)
9/16/11, 11:10โฏAM
Resonant Inelastic and Elastix X-ray Scattering
Talk
More than 70 years after its discovery, the Verwey transition in magnetite (Fe3O4) and the character of the low-temperature phase of this material remains an active and controversial topic. Upon cooling below 123 K, magnetite undergoes a first order transition from cubic to low symmetry accompanied by an increase of the electric resistivity by two orders of magnitude. Different models have...
Dr
W S Lee
(Stanford Institute for Materials and Energy Science, SLAC National Accelerator Lab, USA)
9/16/11, 11:40โฏAM
Resonant Inelastic and Elastix X-ray Scattering
Talk
In the striped nickelate La2-xSrxNiO4, spin order coexists with charge order, whose periodicity is half of spin order. So far, most of the studies on the stripe phase were performed in the thermal equilibrium state by varying temperatures; the dynamics of stripe phase in the time domain when the system is driven-out-of-equilibrium has not yet been studied. Using the x-ray free electron laser...
Dr
R Tobey
(Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton NY 11793, USA)
9/16/11, 12:10โฏPM
Resonant Inelastic and Elastix X-ray Scattering
Talk
Resonant Soft X-Ray Diffraction at the LCLS free electron laser is used to probe stimulated dynamics in two canonical strongly correlated materials. In the first example, Iโll discuss the reconstruction of the 3D scattering volume of the (.25 .25 .5) antiferromagnetic reflection in the layered compound La0.5Sr1.5MnO4 measured at the Mn L-edge. Upon stimulation at near infrared wavelengths,...
Dr
Giacomo Ghiringhelli
(CNR/SPIN and Dipartimento di Fisica, Politecnico di Milano, Italy)
9/16/11, 2:20โฏPM
Resonant Inelastic and Elastix X-ray Scattering
Talk
High resolution soft x-ray RIXS has been quickly evolving and among its initial applications the study of layered cuprates has emerged as probably the most successful. This is due to the favorable combination of an exceptionally strong resonant enhancement at the Cu L3 edge with a particularly simple theoretical description of the RIXS process for the 3d9 configuration. Thus the energies of dd...
Prof.
Marco Grioni
(EPF Lausanne, Switzerland)
9/16/11, 2:50โฏPM
Resonant Inelastic and Elastix X-ray Scattering
Talk
Resonant inelastic x-ray scattering (RIXS) offers a unique view on local and collective excitations in strongly correlated materials, complementary to established techniques like neutrons, optics, or photoemission. The commissioning at the Swiss Light Source of the high-resolution (E/ฮE~10'000) SAXES soft x-ray spectrometer opened the way to measurements of the full spin wave spectrum in the...
Dr
L Hozoi
(Institute for Theoretical Solid State Physics, IFW Dresden, 01171 Dresden, Germany)
9/16/11, 3:20โฏPM
Resonant Inelastic and Elastix X-ray Scattering
Talk
Fully ab initio wavefunction-based methods from modern quantum chemistry are employed for the study of the electronic structure of correlated transition-metal com- pounds. We focus on the computation of N-particle excitations like those probed by optical absorption or RIXS (resonant inelastic x-ray scattering) measurements. The strong correlations are treated within the CASSCF...
122.
Inelastic X-ray Scattering Studies of Cuprate Spin Dynamics: The case of a single La2CuO4 layer
J P Hill
(Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton NY 11793, USA)
9/16/11, 4:20โฏPM
Resonant Inelastic and Elastix X-ray Scattering
Talk
The dynamics of S = ยฝ quantum spins on a 2D square lattice lie at the heart of the mystery of the cuprates. In bulk cuprates such as La2CuO4, the presence of a weak inter-layer coupling (and other interactions) stabilizes 3D Neel order up to high temperatures. In a truly 2D system however, thermal fluctuations melt long range order at any finite temperature. Here, we utilize Cu L-edge RIXS to...
Dr
B J Kim
(Material Science Division, Argonne National Lab, USA)
9/16/11, 4:50โฏPM
Resonant Inelastic and Elastix X-ray Scattering
Talk
Strong relativistic spin-orbit coupling (SOC) in 5d transition metal oxides provides a new route to realizing novel magnetic systems. Depending on the lattice geometry, expected magnetic systems range from conventional Heisenberg magnets to the more exotic Kitaev model and a topological Mott insulator. In the particular case of square lattice geometry relevant for Sr2IrO4, the superexchange...
Dr
A Uldry
(Condensed Matter Theory, Paul Scherrer Institut, Villigen, Switzerland)
9/16/11, 5:20โฏPM
Resonant Inelastic and Elastix X-ray Scattering
Talk
The analysis and interpretation of state-of-the-art synchrotron x-ray measurements often have to rely on the theoretical understanding of the splittings of the atomic energy levels relevant to the case, and the simulation of spectra. Besides electron-electron interaction and spin-orbit coupling, the crystal field may contribute to the multiplets in a non-trivial fashion, particularly when the...
Dr
M Garganourakis
(Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland)
9/16/11, 5:40โฏPM
Resonant Inelastic and Elastix X-ray Scattering
Talk
Manganite compounds have attracted a lot of the scientific interest by virtue of the unusual electronic and magnetic properties among them 'colossal magnetoresistance', and large magnetoresistive response. Here we report the writing, the in-situ observation and erasing of magnetic bits to Pr0.5Ca0.5MnO3 by illuminating with X-rays. Opposite to what is known so far, the antiferromagnetic...
Dr
C Monney
(Research Department Synchrotron Radiation and Nanotechnology, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland,)
9/17/11, 9:00โฏAM
Resonant Inelastic and Elastix X-ray Scattering
Talk
We have performed Resonant Inelastic X-ray Scattering (RIXS) at the Cu L- and O K-resonance at the ADRESS beamline of the Swiss Light Source on the quasi-one-dimensional cuprates Li2CuO2 and CuGeO3, prototype edge-sharing chain compounds showing different magnetic ground states at low temperature. The RIXS spectra display a complicated interplay of low-energy excitations from charge, orbital...
Dr
J Schlappa
(Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin fรผr Materialien und Energie GmbH, Albert-Einstein-Str. 15, 12489 Berlin, Germany)
9/17/11, 9:30โฏAM
Resonant Inelastic and Elastix X-ray Scattering
Talk
Quantum effects become important, when the space symmetry is lowered. In the extreme case of one dimension the fundamental degrees of freedom of the electron can break up into separate quasi-particles carrying the spin, charge or orbital degrees of freedom. Here we report on studies of elementary excitations in quasi 1D cuprates, the spin-ladder/spin-chain compound Sr14Cu24O41 and the...
Dr
K Wohlfeld
(Leibniz Institute for Solid State and Materials Research IFW Dresden, P.O. Box 270116, D-01171 Dresden, Germany)
9/17/11, 9:50โฏAM
Resonant Inelastic and Elastix X-ray Scattering
Talk
Due to the recent advancements in experiment and theory, the resonant inelastic x-ray scattering (RIXS) performed at the L edge of transition metal ions is emerging as a powerful probe to study salient features of the strongly correlated electron systems. For example a recently performed RIXS experiment at the copper L3 edge in quasi one-dimensional Sr2CuO3 reveals orbital excitations with a...
Dr
V Bisogni
(IFW Dresden, Dresden, 01069, Germany)
9/17/11, 10:20โฏAM
Resonant Inelastic and Elastix X-ray Scattering
Talk
Recently, resonant inelastic X-ray scattering (RIXS) on the 1D spin chain system Sr2CuO3 has revealed an unprecedented dispersion of d-d excitations [1]. This result has been under-stood as an effect of strong interaction between spin and orbital degrees-of-freedom taking place within a single chain. In this talk we report on Cu L3 RIXS in quasi 1D CaCu2O3 con-sisting of two coupled spin...
Dr
Jinghua Guo
(Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA)
9/17/11, 11:10โฏAM
Resonant Inelastic and Elastix X-ray Scattering
Talk
There are emerging technologies of using nanostructured semiconductors and charge transfer processes for solar conversion to chemical fuels for energy use and storage. The ability to control the particle size, morphology and composition of nanoparticles is of crucial importance nowadays considering the extensive high-tech applications of 3d metal compounds in the applications of...
Ms
A. Pietzsch
(MAX-lab, Lund University, Lund, Sweden)
9/17/11, 11:40โฏAM
Resonant Inelastic and Elastix X-ray Scattering
Talk
Most fundamental questions regarding the function of complex molecular systems are related to different molecular building blocks and their local electronic and dynamic properties. Resonant Inelastic X-ray Scattering (RIXS) has for a long time allowed access to site-specific electronic structure information on the atomic length scale. As a photon-in/photon-out technique, it is also ideally...
Dr
Ph Wernet
(Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin fรผr Materialien und Energie GmbH, Albert-Einstein-Str. 15, 12489 Berlin, Germany)
9/17/11, 12:00โฏPM
Resonant Inelastic and Elastix X-ray Scattering
Talk
We present our recent results on how we follow both the occupied and unoccupied valence orbitals of dissociating Fe(CO)5 molecules in solution with femtosecond RIXS at the free electron laser LCLS (Stanford, USA).
A pump-laser wavelength of 267 nm is used for resonant metal-to-ligand charge transfer excitation. The evolution of the valence electronic structure is probed with RIXS at the Fe...
Dr
L Journel
(Laboratoire de Chimie Physique โ Matiรจre et Rayonnement, Universitรฉ Pierre et Marie Curie et CNRS, UMR7614, 11, rue Pierre et Marie Curie, 75231 Paris Cedex 05)
9/17/11, 12:20โฏPM
Resonant Inelastic and Elastix X-ray Scattering
Talk
We present main results obtained using RIXS on free molecules, sensitive to sub-femtosecond nuclear dynamics after inner-shell photoexcitation. The core-excited lifetime is used as a characteristic time to probe nuclear rearrangements. Kฮฑ emission spectra at the Cl K edge illustrated the molecular x-ray emission features and their strong correlation with the ab initio potential energy curves...
Dr
M Le Tacon
(Max-Planck-Institut fรผr Festkรถrperforschung, D-70569 Stuttgart, Germany)
9/17/11, 1:50โฏPM
Resonant Inelastic and Elastix X-ray Scattering
Talk
Motivated by the search for the mechanism of high-temperature superconductivity, an intense research effort has been focused on the evolution of the spin excitation spectrum upon doping from the antiferromagnetic (AF) to the superconducting states of the cuprates. Because of technical limitations, however, the experimental investigation of doped cuprates has been largely focused on low energy...
Dr
T Tohyama
(Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502, Japan)
9/17/11, 2:20โฏPM
Resonant Inelastic and Elastix X-ray Scattering
Talk
It has been recognized that both spin and orbital degrees of freedom are the key to understanding the physics of iron arsenides. Theoretical calculations within the random-phase approximation for a five-orbital Hubbard model have nicely explained spin excitations observed by inelastic neutron scattering experiments for antiferromagnetic (AF) phase [1]. In order to clarify the interplay of spin...
Dr
K J Zhou
(Swiss Light Source, Paul Scherrer Institut, CH 5232 Villigen PSI, Switzerland)
9/17/11, 2:50โฏPM
Resonant Inelastic and Elastix X-ray Scattering
Talk
The discovery of iron-based high temperature superconductivity has triggered tremendous research efforts in searching for novel high-Tc superconductors and in understanding the related fundamental physics. Unlike the cuprates whose parent compounds are long-range ordered antiferromagnetic Mott insulators, the iron-based parent compounds are โspin-density waveโ metals with delocalized...
Dr
S Shin
(Institute for Solid State Physics, the University of Tokyo laboratory, Chiba 277-8581, Japan and RIKEN Spring-8, Hyogo 679-5148, Japan)
9/17/11, 3:40โฏPM
Resonant Inelastic and Elastix X-ray Scattering
Talk
Soft X-ray RIXS is a powerful tool for studies of electronic structure of various materials, such as semiconductors, ionic materials, simple metals, and strongly correlated materials. Furthermore, Soft X-ray RIXS is also powerful for the liquids and wet samples. Electronic structures of these materials are very challenging. We will discuss about the electronic states of transition metal...
Dr
S G Chiuzbaian
(UPMC (Univ. Paris 6), Laboratoire de Chimie Physique - Matiรจre et Rayonnement (UMR 7614), F-75005 Paris, France and Synchrotron SOLEIL, F-91192 Gif Sur Yvette, France)
9/17/11, 4:10โฏPM
Resonant Inelastic and Elastix X-ray Scattering
Talk
A new X-ray spectrometer for soft X-rays has recently come into operation at the French national synchrotron facility. The design targets of AERHA (Adjustable Energy Resolution โ High Acceptance) aimed at optimized trade-off between energy resolution and instrument transmission. The instrument covers energies between 50 and 1000 eV with a resolving power in excess of 6000 while maintaining an...
Dr
D J Huang
(National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan)
9/17/11, 4:30โฏPM
Resonant Inelastic and Elastix X-ray Scattering
Talk
Resonant inelastic resonant soft x-ray scattering (RIXS) is an effective spectro-scopic method for unraveling electronic structures of solids, because of recent technological advances in synchrotron radiation sources and beamlines. NSRRC has designed and constructed an experimental setup of RIXS in the soft x-ray re-gime. Ray-tracing results show that the efficiency of a RIXS setup with an...
