A5082657655- Iron-based superconductors research
- Rare-earth and actinide compounds
- Heusler alloys: electronic and magnetic properties
- Machine Learning in Materials Science
- ZnO doping and properties
- Electronic and Structural Properties of Oxides
- Magnetic and transport properties of perovskites and related materials
- Physics of Superconductivity and Magnetism
- Ga2O3 and related materials
- Semiconductor materials and devices
- Inorganic Chemistry and Materials
- Superconductivity in MgB2 and Alloys
- Advanced Materials Characterization Techniques
- Microstructure and Mechanical Properties of Steels
- Electron and X-Ray Spectroscopy Techniques
- Magnetic Properties of Alloys
- Inorganic Fluorides and Related Compounds
- Pigment Synthesis and Properties
- 2D Materials and Applications
- Chalcogenide Semiconductor Thin Films
- Advanced Condensed Matter Physics
- Corporate Taxation and Avoidance
- Surface and Thin Film Phenomena
- Intellectual Capital and Performance Analysis
- Crystal Structures and Properties
Okayama University
2013-2018
Okayama University of Science
2013-2015
The electronic structure of nearly optimally-doped novel superconductor LaO$_{1-x}$F$_x$BiS$_2$ (${\it x}$ = 0.46) was investigated using angle-resolved photoemission spectroscopy (ARPES). We clearly observed band dispersions from 2 to 6 eV binding energy and near the Fermi level E}_{\rm F}$), which are well reproduced by first principles calculations when spin-orbit coupling is taken into account. ARPES intensity map ${\it F}$ shows a square-like distribution around $\Gamma$(Z) point in...
We use core level and valence band soft x-ray photoemission spectroscopy (SXPES) to investigate electronic structure of new BiS$_{2}$ layered superconductor LaO$_{1-x}$F$_{x}$BiS$_{2}$. Core spectra doped samples show a spectral feature at the lower binding energy side Bi 4${f}$ main peak, which may be explained by core-hole screening with metallic states near Fermi ($E_{\rm F}$). Experimental its ${x}$ dependence (higher shift as well appearance $E_{\rm F}$ having dominant 6${p}$ character)...
URu₂Si₂ is a uranium compound that exhibits so-called 'hidden-order' transition at ~17.5 K. However, the order parameter of this second-order as well many its microscopic properties remain unclarified despite considerable research. One key questions in regard concerns type spontaneous symmetry breaking occurring transition; although rotational has been detected, it not clear whether another also occurs. Another question property Fermi-surface gapping momentum space. Here we address these by...
Abstract Unconventional Cooper pairing originating from spin or orbital fluctuations has been proposed for iron-based superconductors. Such may be enhanced by quasi-nesting of two-dimensional electron and hole-like Fermi surfaces (FS), which is considered an important ingredient superconductivity at high critical temperatures (high- T c ). However, the dimensionality FS varies hole electron-doped systems, so precise importance this feature high- materials remains unclear. Here we demonstrate...
The electronic structure of the lightly electron-doped correlated spin-orbit insulator ${\mathrm{Sr}}_{2}{\mathrm{IrO}}_{4}$ has been studied by angle-resolved photoelectron spectroscopy. We have observed coexistence a lower Hubbard band and an in-gap band; momentum dependence latter traces that calculations without on-site Coulomb repulsion. state remained anisotropically gapped in all areas, forming remnant Fermi-surface state, evolving towards Fermi energy carrier doping. These...
We have investigated the changes in band structure and core-level energy of Ca(Fe1-xRhx)2As2 across tetragonal–collapsed tetragonal (T–cT) phase transition using photoemission spectroscopy. Angle-resolved spectroscopy clearly demonstrates that, at Γ point Brillouin zone, a hole-like that crosses Fermi level T lowers its position is completely filled cT phase. This indicates disappearance surface around zone center phase, which gives rise to extinction nesting. The relationship present...
We have performed bulk-sensitive spin-resolved photoemission spectroscopy in order to clarify the intrinsic electronic states of half-metallic ferromagnet CrO2. used CrO2 epitaxial films on TiO2(100), which shows a peak at 1 eV with clear Fermi edge, consistent PES spectrum for In spectra 40 K, while edge was observed spin up (majority spin) state, no level (EF) an energy gap 0.5 below EF were down (minority state. At 300 state closes. These results are resistivity measurements and magnetic...
One of the ultimate goals study iron-based superconductors is to identify common feature that produces high critical temperature (Tc). In early days, based on a weak-coupling viewpoint, nesting between hole- and electron-like Fermi surfaces (FSs) leading so-called $s\pm$ state was considered be one such key feature. However, this theory has faced serious challenge ever since discovery alkali-metal-doped FeSe (AFS) superconductors, in which only FSs with nodeless superconducting gap are...
Using high-resolution spin-resolved photoemission spectroscopy, we observe a thermal spin depolarization to which all spin-polarized electrons contribute. Furthermore, distinct minority state near the Fermi level and corresponding that seldom contributes demagnetization. The origin of this has been identified as many-body effect characteristic half-metallic ferromagnets. Our investigation opens an experimental field itinerant ferromagnetic physics focusing on phenomena with sub-meV energy scale.
We have performed a photoemission spectroscopy (PES) study of CeM2Al10 (M = Fe, Ru, and Os) to directly observe the electronic structure involved in unusual magnetic ordering. Soft X-ray resonant (SXR) PES provides spectroscopic evidence hybridization between conduction Ce 4f electrons (c-f hybridization) order strength (Ru < Os Fe). High-resolution (HR) CeRu2Al10 CeOs2Al10, as compared with that CeFe2Al10, identifies two structures can be ascribed induced by c-f antiferromagnetic ordering,...
BiS2-based layered superconductors are new superconductors, having been paid special attention due to the crystal structure and characteristic electronic that can lead exotic mechanism of superconductivity as well cooperation ordered phases. In this article, we report valence band dispersions Fermi surface topology LaO1-xFxBiS2 (x = 0.23, Tc < 2 K) studied by angle-resolved photoemission spectroscopy, compared them with those 0.46, 3.1 K). We discuss experimental x dependent structures its...
Bulk electronic structure of novel layered superconductor Nd(O,F)BiS2 was studied by using soft x-ray angle-resolved photoelectron spectroscopy (ARPES). Electron-like Fermi surface centered at the X(R) point observed, consistent with earlier ARPES reports on surface-sensitive VUV light source. Based comparison between and La(O,F)BiS2, we discuss possible important factors for superconductivity in this series material.
We studied the electronic structure of Ca10(Pt4As8)(Fe2−xPtxAs2)5 for two platinum concentrations with different Tc using ARPES. From carrier number estimated from areas FS sheets, we found that Pt substitution induces electron doping into Fe2As2 layers (effectively electrons per atom). In addition, nesting condition in x = 0.25 is stronger than 0.42, indicating close correlation between and Tc.