Chemical shifts of metallic and non-metallic Al-Re-Si approximant crystals studied by EELS and SXES

S. Koshiya, M. Terauchi, Y. Takagiwa, K. Yamada, I. Kanazawa, K. Kimura

    Research output: Contribution to journalArticlepeer-review

    2 Citations (Scopus)

    Abstract

    Chemical shifts of approximant crystals of 1/0-Al12Re (1/0-metallic), 1/1-Al73Re15Si12 (1/1-metallic) and 1/1-Al73Re17Si10 (1/1-non-metallic) were examined by using electron energy-loss spectroscopy (EELS) and soft-X-ray emission spectroscopy (SXES). Al L-shell excitation EELS spectra of these alloys showed an apparent chemical shift only for the 1/1-non-metallic alloy to the larger binding energy side by 0.2 eV. Al-Kα, Re-Mα and Si-Kα emission SXES spectra also showed a shift to the larger binding energy side only for 1/1-non-metallic alloy. 1/0-metallic and 1/1-metallic alloys did not show any chemical shift in EELS and SXES experiments. Chemical shifts were observed only in larger binding energy side compared with pure materials. This implies the decrease of valence charge at constituent atomic sites of 1/1-non-metallic alloy compared with 1/0-metallic, 1/1-metallic and pure materials. The decreased charges should distribute intermetallic sites, which should be related to a formation of covalent bonding among Al atomic sites reported by maximum-entropy method (MEM)/Rietveld analysis on this material. This relation between chemical shift and covalent bonding nature of this approximant alloy may support the presence of covalent bonding in Al-based quasicrystals.

    Original languageEnglish
    Pages (from-to)1711-1718
    Number of pages8
    JournalPhilosophical Magazine
    Volume94
    Issue number15
    DOIs
    Publication statusPublished - 2014 May 24

    Keywords

    • Chemical shift
    • Covalent bonding
    • EELS
    • Electronic structure
    • Quasicrystal
    • SXES
    • approximant Al-Re-Si alloy

    ASJC Scopus subject areas

    • Condensed Matter Physics

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