title: Spatial distribution of electrons near the Fermi level in the metallic LaB6through accurate X-ray charge density study.
abstract: Charge densities of iso-structural metal hexaborides, a transparent metal LaB6and a semiconductor BaB6, have been determined using the d > 0.22 Å ultra-high resolution synchrotron radiation X-ray diffraction data by a multipole refinement and a maximum entropy method (MEM). The quality of the experimental charge densities was evaluated by comparison with theoretical charge densities. The strong inter-octahedral and relatively weak intra-octahedral boron-boron bonds were observed in the charge densities. A difference of valence charge densities between LaB6and BaB6was calculated to reveal a small difference between isostructural metal and semiconductor. The weak electron lobes distributed around the inter B6octahedral bond were observed in the difference density. We found the electron lobes are the conductive π-electrons in LaB6from the comparison with the theoretical valence charge density. We successfully observed a spatial distribution of electrons near the Fermi level from the X-ray charge density study of the series of iso-structural solids.
authors.affiliation: Division of Physics, Faculty of Pure and Applied Sciences, Center for Integrated Research in Fundamental Science and Engineering &Tsukuba Research Center for Interdisciplinary Materials Science, University of Tsukuba. 1-1-1, Tennodai, Tsukuba, Ibaraki, 305-8571, Japan.
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Kasai
authors.affiliation: Division of Physics, Faculty of Pure and Applied Sciences, Center for Integrated Research in Fundamental Science and Engineering &Tsukuba Research Center for Interdisciplinary Materials Science, University of Tsukuba. 1-1-1, Tennodai, Tsukuba, Ibaraki, 305-8571, Japan.
authors.forename: Eiji
authors.initials: E
authors.lastname: Nishibori