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Agui, Akane; Kmbre, T.*; Sthe, C.*; Nordgren, J.*; Usuda, Manabu; Saito, Tomohiko*; Moritomo, Yutaka*
Journal of Electron Spectroscopy and Related Phenomena, 144-147, p.589 - 592, 2005/06
Times Cited Count:1 Percentile:5.68(Spectroscopy)Current research in the perovskite and layered perovskite-type manganese oxides has expanded to include the study of electronic and magnetic properties such as the colossal magnetoresistance (CMR), orbital ordering and charge ordering. The O K soft X-ray emission and absorption spectra (XES and XAS) of LaSrMnO were measured at selected excitation energies in order to investigate the electronic structure. The measurements were carried out by using a soft X-ray emission spectrometer at beamline BW3 at HASYLAB, Germany. The dependence of O K XES on excitation-energy was observed. It is attributed the different site of oxygen ions.
Nishikawa, Yunori; Usuda, Manabu; Igarashi, Junichi*
Journal of the Physical Society of Japan, 73(11), p.3171 - 3176, 2004/11
Times Cited Count:3 Percentile:26.42(Physics, Multidisciplinary)no abstracts in English
Usuda, Manabu; Igarashi, Junichi*; Kodama, Akio*
Physical Review B, 69(22), p.224402_1 - 224402_5, 2004/06
Times Cited Count:20 Percentile:65.71(Materials Science, Multidisciplinary)Magnetic resonant X-ray scattering (MRXS) at the edge of Ga in an antiferromagnetic phase of UGa is studied on the basis of a band-structure calculation. We find that a relatively large orbital polarization in the unoccupied states of the Ga band is induced by the orbital polarizations at neighboring U atoms through the Ga and U hybridization, and thereby leading to the large MRXS intensity.
Nishikawa, Yunori; Usuda, Manabu; Igarashi, Junichi*; Shoji, Hironobu*; Iwazumi, Toshiaki*
Journal of the Physical Society of Japan, 73(4), p.970 - 975, 2004/04
Times Cited Count:6 Percentile:41.15(Physics, Multidisciplinary)no abstracts in English
Usuda, Manabu; Hamada, Noriaki*; Shiraishi, Kenji*; Oshiyama, Atsushi*
Japanese Journal of Applied Physics, Part 2, 43(3B), p.L407 - L410, 2004/03
Times Cited Count:31 Percentile:71.96(Physics, Applied)We report first-principles electronic band-structure calculations of InN by using the all-electron full-potential linearized augmented-plane-wave (FLAPW) method in the approximation (GWA), and provide the reliable theoretical bandgap of InN. Our calculation suggests that InN is a narrow-gap semiconductor and strongly supports the recently reported smaller bandgaps.
Usuda, Manabu; Takahashi, Manabu*; Igarashi, Junichi
Physical Review B, 69(1), p.014408_1 - 014408_7, 2004/01
Times Cited Count:11 Percentile:49.46(Materials Science, Multidisciplinary)We have investigated the magnetic X-ray scattering spectra around the edge of Ni in antiferromagnetic NiO on the basis of an calculation. By taking account of orbital polarization through the spin-orbit interaction, we reproduce well the spectra obtained experimentally. We have analyzed the contributions of the resonant dipolar, quadrupolar, and non-resonant scattering processes and clarified the mechanism of the resonant magnetic X-ray scattering.
Usuda, Manabu; Hamada, Noriaki*; Shiraishi, Kenji*; Oshiyama, Atsushi*
Physica Status Solidi (C), 0(7), p.2733 - 2736, 2003/12
Times Cited Count:2 Percentile:68.29(Crystallography)The electronic band-structures of wurtzite-type GaInN are calculated by using an all-electron FLAPW method in the approximation(GWA). Our calculations show that the bandgap of InN is smaller than 1 eV, and strongly support the recently observed smaller bandgaps.
Akao, Tadahiro*; Azuma, Yusuke; Usuda, Manabu; Nishihata, Yasuo; Mizuki, Junichiro; Hamada, Noriaki*; Hayashi, Naoaki*; Terashima, Takahito*; Takano, Mikio*
Physical Review Letters, 91(15), p.156405_1 - 156405_4, 2003/10
Times Cited Count:34 Percentile:79.55(Physics, Multidisciplinary)X-ray anomalous diffraction, together with a band structure calculation, was employed to obtain a quantitative comprehension of the charge-ordering state in a single-crystalline CaFeO thin film. The experimental results show a characteristic energy dispersion of the near inhibited reflection at 150, implying Fe atoms split into two distinct states. The energy dispersion is in good agreement with the calculated spectrum based on LDA+U scheme. The calculation reveals an electronic configuration of the Fe 3d orbital follows a localization in the oxygen orbital surrounds one of the distinct Fe atoms.
Takahashi, Manabu*; Usuda, Manabu; Igarashi, Junichi
Physical Review B, 67(6), p.064425_1 - 064425_7, 2003/02
Times Cited Count:21 Percentile:68.18(Materials Science, Multidisciplinary)We study the magnetic resonant X-ray scattering (RXS) spectra around the K edge of Cu in KCuF on the basis of an ab initio calculation. We use the full-potential linearlized augumented plane wave method in the LDA+U scheme, and introduce the lattice distortion as inputs of the calculation. We obtain finite intensity on magnetic superlattice spots by taking account of the spin-orbit interaction. We also calculate the RXS intensity on orbital superlattice spots. It is found that the intensity increases with increasing Jahn-Teller distortion.