Yuki Wakisaka

Insulator-to-Superconductor Transition upon Electron Doping in a BiS2-Based Superconductor Sr1−xLaxFBiS2

Effects of electron doping on the BiS2-based superconductors Sr1−xLaxFBiS2 (0 ≤ x ≤ 0.6) have been investigated using the systematically synthesized polycrystals by means of x-ray diffraction, x-ray absorption spectroscopy, transport and thermodynamic measurements. The pristine compound is a band insulator with the BiS2 layer, which accommodates electron carriers through the La substitution for Sr, as evidenced by the change in x-ray absorption spectra reflecting the occupancy of Bi 6p orbitals. With increasing the carrier density, the resistivity progressively decreases and a bad metallic state appears for x ≥ 0.45, where bulk superconductivity manifests itself below approximately 3 K. The value of Tc gradually increases with decreasing x from 0.6 to 0.45 and immediately decreases down to zero at the critical concentration of x ∼ 0.4, resulting in an insulator–superconductor transition highly sensitive to the carrier density. Thermodynamic measurements furthermore have revealed the possible enhancement o...

Orbital degeneracy and Peierls instability in the triangular-lattice superconductor Ir 1-xPt xTe 2

We have studied the electronic structure of the triangular lattice Ir

Dynamics of Photoelectrons and Structural Changes of Tungsten Trioxide Observed by Femtosecond Transient XAFS

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Electronic structure of LaFeAsO: yz/zx orbital degeneracy and excitonic instability

Pt

Doping-Dependent and Orbital-Dependent Band Renormalization in Ba(Fe1-xCox)2As2 Superconductors

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Electronic Structure of Superconducting and Non-superconducting Pr2Ba4Cu7O15-δ Revealed by Photoemission Spectroscopy

Te

Impact of Mn–O–O–Mn superexchange pathways in a honeycomb lattice Mn oxide with small charge-transfer energy

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Development of Surface Fluorescence X-ray Absorption Fine Structure Spectroscopy using a Laue-Type Monochromator

superconductor using photoemission spectroscopy and model calculations. Ir

Design of Service Ecosystem Based on Interactive Design Support in the Case of Job-Hunting Support Services

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Electronic structure of Ca3 Co4 O9 studied by photoemission spectroscopy: Phase separation and charge localization

core-level photoemission spectra show that Ir