A5012068288- Rare-earth and actinide compounds
- Magnetic properties of thin films
- Iron-based superconductors research
- Advanced Condensed Matter Physics
- Advanced Chemical Physics Studies
- Magnetic and transport properties of perovskites and related materials
- Physics of Superconductivity and Magnetism
- Magnetic Properties of Alloys
- Electron and X-Ray Spectroscopy Techniques
- X-ray Spectroscopy and Fluorescence Analysis
- Inorganic Chemistry and Materials
- Advanced Materials Characterization Techniques
- Electronic and Structural Properties of Oxides
- Heusler alloys: electronic and magnetic properties
- Crystallography and Radiation Phenomena
- Magnetism in coordination complexes
- Transition Metal Oxide Nanomaterials
- Nuclear Materials and Properties
- Semiconductor materials and interfaces
- Magnetic Properties and Applications
- Atomic and Molecular Physics
- X-ray Diffraction in Crystallography
- High-pressure geophysics and materials
- Advanced Electron Microscopy Techniques and Applications
- Ga2O3 and related materials
Ritsumeikan University
2015-2025
SPring-8
2015-2025
Osaka University
2005-2014
University of Augsburg
2006
Hiroshima University
2004
Chonnam National University
2003
Nagoya Institute of Technology
2001
Toneyama National Hospital
2001
Osaka Prefecture University
2000
Japan Synchrotron Radiation Research Institute
1999
We report high-resolution high-energy photoemission spectra together with parameter-free $\mathrm{L}\mathrm{D}\mathrm{A}+\mathrm{D}\mathrm{M}\mathrm{F}\mathrm{T}$ (local density approximation $+$ dynamical mean-field theory) results for ${\mathrm{S}\mathrm{r}}_{1\ensuremath{-}x}{\mathrm{C}\mathrm{a}}_{x}{\mathrm{V}\mathrm{O}}_{3}$, a prototype $3{d}^{1}$ system. In contrast to earlier investigations the bulk are found be insensitive $x$. The good agreement between experiment and theory...
Strong circular dichroism is found in 2-dimensional angular distribution patterns of the Si 2p photoelectrons from Si(001) surface, which has no chirality and magnetism. The forward focusing peaks pattern rotate clockwise or counterclockwise when helicity incident circularly polarized light reversed. These rotations are explained by rotational motion around nuclei. This first direct observation electrons clarifies correspondence between classical quantum mechanical ideas momentum.
We have examined the valence-band electronic structures of gold and silver in same column periodic table with nominally filled d orbitals by means a recently developed polarization-dependent hard x-ray photoemission. Contrary to common expectation, it is found that 5d-orbital electrons contribute prominently conduction gold, while are some extent free-electron-like negligible 4d contribution, which could be related well-known fact more stable than air. The electron correlation effects...
We report the Fermi surfaces of superconductor ${\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4}$ and nonsuperconductor ${\mathrm{Sr}}_{1.8}{\mathrm{Ca}}_{0.2}{\mathrm{RuO}}_{4}$ probed by bulk-sensitive high-energy angle-resolved photoemission. It is found that there one square-shaped hole-like, electron-like, circle-shaped electron-like surface in both compounds. These results provide direct evidence for nesting instability giving rise to magnetic fluctuations. Our study clarifies electron correlation...
Sm-based heavy-fermion compound ${\mathrm{SmOs}}_{4}{\mathrm{Sb}}_{12}$ has been investigated by soft x-ray ($h\ensuremath{\nu}=1070--1600\text{ }\text{ }\mathrm{eV}$) and hard (HX; $h\ensuremath{\nu}=7932\text{ spectroscopy. The HX photoemission spectroscopy clearly demonstrates that the strongly mixed-valence state coexist in bulk. It is found Sm valence decreases below 100 K, indicating Kondo coherence develops with approaching proposed temperature. Our theoretical analyses suggest origin...
In this study, we investigate the bulk electronic structure of Pb-substituted ${\mathrm{LaO}}_{0.5}{\mathrm{F}}_{0.5}{\mathrm{BiS}}_{2}$ single crystals, using two types hard x-ray spectroscopy. High-energy-resolution fluorescence-detected absorption spectroscopy revealed a spectral change at low temperatures. Using density functional theory (DFT) simulations, find that temperature-induced originates from structural phase transition, similar to pressure-induced transition in...
The spin reorientation transition in fcc Co/Ni/Cu(001) epitaxial ultrathin films as a function of Co and Ni film thickness is studied by the combination photoelectron emission microscopy x-ray magnetic-circular-dichroism spectroscopy at ${L}_{2,3}$ edge. This microspectroscopic technique allows one to extract local quantitative information about magnetic properties on submicrometer scale. Domain images range 1.4--2.6 atomic monolayers (ML) 11--14 ML show that occurs both thicknesses....
We have investigated the magnetic electronic structures of PtMnSb, NiMnSb, ${\mathrm{Ni}}_{2}\mathrm{MnSb},$MnSb, MnAlGe, and ${\mathrm{Mn}}_{2}\mathrm{Sb}$ by soft-x-ray absorption spectroscopy (XAS) circular dichroism (MCD) measurements in Mn $2p$ core region. Different degrees electron itinerancy $3d$ states are discussed. The large orbital angular momentum electrons is revealed for MnSb MCD spectrum. In addition, XAS spectra measured Sb $3d,$ Ni $2p,$ Pt $4f$ excitation regions. An...
By use of high-resolution soft X-rays, intrinsic temperature dependences bulk Yb 4f photoelectron spectra were obtained for fractured surfaces high-purity YbAl 3 single crystals. The not only 13 but also 12 final states are analyzed by noncrossing approximation (NCA) calculation the f 14 , and initial based on impurity Anderson model (SIAM). In order to consistently interpret both states, however, it is found that a constant set parameters hybridization strength Δ, bare energy ε electron...
We present a calculation of magnetic circular dichroism in 3 d and 4 core X-ray absorption spectra rare earth systems assuming that trivalent ion is placed an infinitesimal uniform field. The covers all elements between Ce Tm. Features the are explained by elementary considerations transition matrix polarized light, spin-orbit coupling hole, exchange interaction hole f electron.
Soft and hard x-ray photoelectron spectroscopy has been performed for one of the heavy fermion system $\mathrm{Ce}{\mathrm{Ru}}_{2}{\mathrm{Si}}_{2}$ a $4f$-localized ferromagnet $\mathrm{Ce}{\mathrm{Ru}}_{2}{\mathrm{Ge}}_{2}$ in paramagnetic phase. The three-dimensional band structures Fermi surface shapes have determined by soft $h\ensuremath{\nu}$-dependent angle-resolved spectroscopy. differences topology non-$4f$ electronic between are qualitatively explained band-structure calculation...
We have investigated the electronic structures of recently discovered superconductor FeSe by soft-x-ray and hard-x-ray photoemission spectroscopy with high-bulk sensitivity. The large $\text{Fe}\text{ }3d$ spectral weight is located in vicinity Fermi level $({E}_{F})$, which demonstrated to be a coherent quasiparticle peak. Compared results band-structure calculation local-density approximation, band narrowing energy shift toward ${E}_{F}$ are found, suggesting an importance electron...
Inorganic photochromic materials offer several advantages over organic compounds, including relatively inexpensive and higher thermal stability. However, tuning their color with the same component has remained a significant challenge. In this study, we demonstrate that of Cu‐doped ZnS nanocrystals (NCs), which is initially pale yellow before light irradiation, can be tuned from gray to brown by adjusting surface stoichiometry Zn S, controlled through use thiol non‐thiol ligands. Several...
Inorganic photochromic materials offer several advantages over organic compounds, including relatively inexpensive and higher thermal stability. However, tuning their color with the same component has remained a significant challenge. In this study, we demonstrate that of Cu‐doped ZnS nanocrystals (NCs), which is initially pale yellow before light irradiation, can be tuned from gray to brown by adjusting surface stoichiometry Zn S, controlled through use thiol non‐thiol ligands. Several...
The magnetic circular dichroism (MCD) of core-level absorption [x-ray spectroscopy (XAS)] spectra in the soft x-ray region has been measured for ferromagnetic Heusler alloys ${\mathrm{Co}}_{2}\mathrm{TiSn},$ ${\mathrm{Co}}_{2}\mathrm{ZrSn},$ and ${\mathrm{Co}}_{2}\mathrm{NbSn}.$ many-peak structures which are clearly observed Co $2\stackrel{\ensuremath{\rightarrow}}{p}3d$ XAS-MCD cannot be well explained by atomic multiplet calculations but better $3d$ unoccupied states predicted linear...
“Bulk-sensitive” Ce 3 d -4 f resonance photoemission (RPES) with an unprecedentedly high resolution has revealed a clear difference of bulk 4 spectral weights heavy fermion system CeRu 2 Si and Ge in the region tail Kondo peak its spin-orbit partner. The significant both materials is strong contrast to mutually similar “surface-sensitive” RPES. obtained bulk-sensitive spectra are well reproduced by single impurity model. Consideration crystalline electric field splitting important for...
Soft x-ray excited angle-resolved photoemission spectroscopy (ARPES) is performed for the valence bands of quasi-one-dimensional ${\mathrm{V}}_{6}{\mathrm{O}}_{13}$ and $\mathrm{Sr}\mathrm{Cu}{\mathrm{O}}_{2}$ in order to reveal behavior strongly correlated $\mathrm{V}\phantom{\rule{0.2em}{0ex}}3d$ $\mathrm{Cu}\phantom{\rule{0.2em}{0ex}}3d$ states. The resonance enhancement state $\mathrm{V}\phantom{\rule{0.2em}{0ex}}2p$ core excitation high photoionization cross section states compared with...
By virtue of the soft x-ray angle-resolved photoelectron spectroscopy, three-dimensional bulk fermiology has been successfully performed for a strongly correlated Ce compound, ferromagnet CeRu2Ge2 in paramagnetic phase. A clear difference Fermi surface topology from either band calculation or de Haas-van Alphen results ferromagnetic phase is observed and interpreted by considering 4f contribution to surfaces
The lattice parameter of FCC ( gamma -)Fe precipitates in a Cu matrix is investigated as function the size precipitates. With prolonged aging, noncoherent -Fe with about 0.2% smaller spacings than coherent ones are found. structural phase transition, magnetic structure and Neel temperature this new state studied using X-ray neutron diffraction methods. Antiferromagnetic ordering takes place accompanying transition state. observed slightly higher previously reported value TN=67 K. Various...
Hard and soft x-ray photoelectron spectroscopy was performed for core valence electrons in solid compounds containing V O atoms. The single-nucleus recoil effects on emission were observed the form of shifts all levels band a heavy Fermion material LiV2O4, whereas such negligible VO2 even high-temperature metal phase. V5O9 V2O3 are found to be between. These differences ascribable difference relative spectral weight 2p component near Fermi level.
We have studied the electronic structures of GdX (X: P, As, Sb, Bi) by means X-ray photoemission, bremsstrahlung isochromat and vacuum ultraviolet inverse photoemission spectroscopy. found monotonous energy shifts Gd 3 d , 4 f levels from GdP to GdBi. Such systematic are attributed reduced crystal field splitting 5 state through GdX. The occupied valence band is dominated X p state. be much different those Gd-derived states, but consistently interpreted calculation.