N. Kamakura

Bulk screening in core-level photoemission from Mott-Hubbard and charge-transfer systems

We report bulk-sensitive hard x-ray shn = 5.95 keVd core-level photoemission spectroscopy sPESd of single crystal V1.98Cr0.02O3 and the high-Tc cuprate Bi2Sr2CaCu2O8+d sBi2212d .V 1.98Cr0.02O3 exhibits low binding energy “satellites” to the V 2 p “main lines” in the metallic phase, which are suppressed in the antiferromagnetic insulator phase. In contrast, the Cu 2 p spectra of Bi2212 do not show temperature-dependent features, but a comparison with soft x-ray PES indicates a large increase in the 2p 5 3d 9 satellites or 3d 9 weight in the bulk. Cluster model calculations, including a full multiplet structure and a screening channel derived from the coherent band at the Fermi energy, give very satisfactory agreement with the experiments.

Surface structure and segregation of ordered Pt3Co(110) induced by oxygen

Abstract We have investigated the surface structure and segregation induced by oxygen adsorption on the ordered Pt3Co(110) alloy using low-energy electron diffraction (LEED), Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). For the clean Pt3Co(110) surface, two different LEED patterns of 1×1 and 2×1 were observed depending on the annealing temperature, which had different Pt (237eV)/Co (LMM) AES intensity ratios. With increasing oxygen exposure at the substrate temperature of 300–500°C, the 2×1 LEED pattern of the clean Pt3Co(110) surface changed to c(2×4), 1×2, and 1×2+2×1+extra spots patterns, successively, and the Pt/Co AES intensity ratios showed a drastic decrease. Co 2p and O 1s core level spectra by XPS and normal emission valence band spectra by UPS indicated that a Co monoxide overlayer is formed due to a reaction with oxygen at a high-temperature substrate. From these results, it was found that the observed several surface structures are due to the reaction between the segregated Co and adsorbed O atoms to form the stoichiometric CoO-typed overlayer.

Temperature-dependent Eu 3 d − 4 f x-ray absorption and resonant photoemission study of the valence transition in Eu Ni 2 ( Si 0.2 Ge 0.8 ) 2

We study the mixed valence transition (

Hard X-ray Photoemission Spectroscopy of Temperature-Induced Valence Transition in EuNi2(Si0.20Ge0.80)2

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Intermolecular Interaction by Apical Oxygen in Titanyl Phthalocyanine

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Spin-resolved core-level and valence-band photoemission spectroscopy of ferromagnetic MnAs

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Electronic structure of Si(113)2 × 2-Cs surface studied by ARUPS

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Spin- and angle-resolved photoemission spectroscopy of ferromganetic MnAs

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