Structural properties and thermodynamic stability of Ba-doped silicon type-I clathrates synthesized under high pressure

Akiko Kitano, Koji Moriguchi, Mitsuharu Yonemura, Shinji Munetoh, Akira Shintani, Hiroshi Fukuoka, Shoji Yamanaka, Eiji Nishibori, Masaki Takata, Makoto Sakata

研究成果: ジャーナルへの寄稿学術誌査読

42 被引用数 (Scopus)

抄録

We present a joint experimental and theoretical study of the stability and structural properties of Ba-doped silicon type-I clathrates Ba8Si46 synthesized under high pressures. The thermodynamic stability of Ba8Si46 under high pressure has been discussed from the total energy calculations of some barium silicides within the local density approximation (LDA). We have theoretically found that pressure favors the formation of the clathrate phase as experimentally observed. We have also performed a synchrotron x-ray-diffraction experiment of Ba8Si46 prepared under high pressures. Some of the missing endohedral Ba elements in the small cage of Si(20) have been observed by x-ray crystallography, while big cages of Si(24) are found to be completely occupied by Ba elements. The stabilization energies of Ba atoms in the endohedral sites estimated within the present LDA calculation suggest that this is presumably attributed to the energetical site preference of Ba atoms between d(6) and a(2) sites. In addition, the isothermal parameter of Ba in the big cage of Si(24) has been found to be larger than that in the small Si(20) unit, which is consistent with some theoretical predictions in earlier works.

本文言語英語
論文番号045206
ページ(範囲)452061-452069
ページ数9
ジャーナルPhysical Review B - Condensed Matter and Materials Physics
64
4
DOI
出版ステータス出版済み - 7月 15 2001
外部発表はい

!!!All Science Journal Classification (ASJC) codes

  • 電子材料、光学材料、および磁性材料
  • 凝縮系物理学

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