Determination of a (4 × 4) structure formed on a Cu(0 0 1) surface by adsorption of calcium

Hisashi Yoshida, Shougo Higashi, Tetsuroh Shirasawa, Seigi Mizuno, Hiroshi Tochihara, Xiangdong Liu, Fumio Komori

    研究成果: ジャーナルへの寄稿学術誌査読

    1 被引用数 (Scopus)

    抄録

    The adsorption of calcium (Ca) atoms on a Cu(0 0 1) surface has been studied by low-energy electron diffraction (LEED) at 130, 300 and 400 K. It is found that a (4 × 4) was the only LEED pattern appeared at 400 K while a quasi-hexagonal structure was formed in a wide range of submonolayer coverage at 130 K. At 300 K, the (4 × 4) LEED spots were broad and weak. The (4 × 4) structure formed at 400 K was determined by a tensor LEED I-V analysis. It is a new-type of surface alloys consisting of five substitutional Ca atoms, nine surface Cu atoms, and two atomic vacancies in the unit cell. In spite of a quite large size-difference between Ca (3.94 Å) and Cu (2.55 Å) atoms, all Ca atoms are located at the substitutional sites. Among surface alloys so far reported, the atomic size ratio between Cu and Ca in the (4 × 4), 1.54, is the largest. Optimized structural parameters reveal that large lateral displacements of surface Cu atoms, being enabled by the appearance of the vacancies, allow the formation of the (4 × 4) structure.

    本文言語英語
    ページ(範囲)659-663
    ページ数5
    ジャーナルSurface Science
    603
    4
    DOI
    出版ステータス出版済み - 2月 15 2009

    !!!All Science Journal Classification (ASJC) codes

    • 凝縮系物理学
    • 表面および界面
    • 表面、皮膜および薄膜
    • 材料化学

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