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

Physical Review B - Condensed Matter and Materials Physics Volume 64 Issue 4 Page 045206- published_at 2001-07-15
アクセス数 : 821
ダウンロード数 : 270

今月のアクセス数 : 2
今月のダウンロード数 : 0
File
PhysRevB_64_045206.pdf 617 KB 種類 : fulltext
Title ( eng )
Structural properties and thermodynamic stability of Ba-doped silicon type-I clathrates synthesized under high pressure
Creator
Kitano Akiko
Moriguchi Koji
Yoneyama Mitsuharu
Munetoh Shinji
Shintani Akira
Nishibori Eiji
Takata Masaki
Sakata Makoto
Source Title
Physical Review B - Condensed Matter and Materials Physics
Volume 64
Issue 4
Start Page 045206
Abstract
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.
NDC
Physics [ 420 ]
Language
eng
Resource Type journal article
Publisher
American Physical Society
Date of Issued 2001-07-15
Rights
Copyright (c) 2001 American Physical Society
Publish Type Version of Record
Access Rights open access
Source Identifier
[NCID] AA11187113
[ISSN] 1098-0121
[DOI] 10.1103/PhysRevB.64.045206
[DOI] http://dx.doi.org/10.1103/PhysRevB.64.045206