4,031 research outputs found

    Strongly spin-orbit coupled two-dimensional electron gas emerging near the surface of polar semiconductors

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    We investigate the two-dimensional (2D) highly spin-polarized electron accumulation layers commonly appearing near the surface of n-type polar semiconductors BiTeX (X = I, Br, and Cl) by angular-resolved photoemission spectroscopy. Due to the polarity and the strong spin-orbit interaction built in the bulk atomic configurations, the quantized conduction-band subbands show giant Rashba-type spin-splitting. The characteristic 2D confinement effect is clearly observed also in the valence-bands down to the binding energy of 4 eV. The X-dependent Rashba spin-orbit coupling is directly estimated from the observed spin-split subbands, which roughly scales with the inverse of the band-gap size in BiTeX.Comment: 15 pages 4 figure

    Lupus erythematosus profundus (lupus panniculitis) induced by interferon-beta in a multiple sclerosis patient

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    ArticleJOURNAL OF CLINICAL NEUROSCIENCE. 14(10): 997-1000 (2007)journal articl

    Size variance of motor evoked potential at initiation of voluntary contraction in palsy of conversion disorder

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    ArticlePSYCHIATRY AND CLINICAL NEUROSCIENCES. 62(3): 286-292(2008)journal articl

    Three-dimensional bulk band dispersion in polar BiTeI with giant Rashba-type spin splitting

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    In layered polar semiconductor BiTeI, giant Rashba-type spin-split band dispersions show up due to the crystal structure asymmetry and the strong spin-orbit interaction. Here we investigate the 3-dimensional (3D) bulk band structures of BiTeI using the bulk-sensitive hνh\nu-dependent soft x-ray angle resolved photoemission spectroscopy (SX-ARPES). The obtained band structure is shown to be well reproducible by the first-principles calculations, with huge spin splittings of ∼300{\sim}300 meV at the conduction-band-minimum and valence-band-maximum located in the kz=π/ck_z=\pi/c plane. It provides the first direct experimental evidence of the 3D Rashba-type spin splitting in a bulk compound.Comment: 9 pages, 4 figure

    Bulk and surface-sensitive high-resolution photoemission study of Mott-Hubbard systems SrVO3_3 and CaVO3_3

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    We study the electronic structure of Mott-Hubbard systems SrVO3_{3} and CaVO3_3 with bulk and surface-sensitive high-resolution photoemission spectroscopy (PES), using a VUV laser, synchrotron radiation and a discharge lamp (hνh\nu = 7 - 21 eV). A systematic suppression of the density of states (DOS) within ∼\sim 0.2 eV of the Fermi level (EFE_F) is found on decreasing photon energy i.e. on increasing bulk sensitivity. The coherent band in SrVO3_{3} and CaVO3_3 is shown to consist of surface and bulk derived features, separated in energy. The stronger distortion on surface of CaVO3_{3} compared to SrVO3_{3} leads to higher surface metallicity in the coherent DOS at EFE_F, consistent with recent theory.Comment: 4 pages 5 figures (including 2 auxiliary figures); A complete analysis of the spectra based on the surface and bulk analysis shows in auxiliary figures Fig. A1 and A

    Use of CD134 as a primary receptor by the feline immunodeficiency virus

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    Feline immunodeficiency virus (FIV) induces a disease similar to acquired immunodeficiency syndrome (AIDS) in cats, yet in contrast to human immunodeficiency virus (HIV), CD4 is not the viral receptor. We identified a primary receptor for FIV as CD134 (OX40), a T cell activation antigen and costimulatory molecule. CD134 expression promotes viral binding and renders cells permissive for viral entry, productive infection, and syncytium formation. Infection is CXCR4-dependent, analogous to infection with X4 strains of HIV. Thus, despite the evolutionary divergence of the feline and human lentiviruses, both viruses use receptors that target the virus to a subset of cells that are pivotal to the acquired immune response

    Fermi-surface reconstruction involving two Van Hove singularities across the antiferromagnetic transition in BaFe2As2

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    We report an angle-resolved photoemission study of BaFe2As2, a parent compound of iron-based superconductors. Low-energy tunable excitation photons have allowed the first observation of a saddle-point singularity at the Z point, as well as the Gamma point. With antiferromagnetic ordering, both of these two van Hove singularities come down below the Fermi energy, leading to a topological change in the innermost Fermi surface around the kz axis from cylindrical to tear-shaped, as expected from first-principles calculation. These singularities may provide an additional instability for the Fermi surface of the superconductors derived from BaFe2As2.Comment: 14 pages, 4 figures, 1 tabl
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