Phys. Rev. Lett. 90, 155503 (2003) [4 pages]

High-Pressure Raman Study of Ba Doped Silicon Clathrate

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Tetsuji Kume1 *, Hiroshi Fukuoka2, Toshihiro Koda3, Shigeo Sasaki1,3, Hiroyasu Shimizu1,3, and Shoji Yamanaka2
1Department of Materials Science and Technology, Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan
2Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, Higasi-Hiroshima 739-8527, Japan
3Environmental and Renewable Energy Systems, Graduate School of Engineering, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan

Received 20 December 2002; published 15 April 2003

Vibrational properties of Ba doped Si clathrate are investigated at high pressures up to 20 GPa by Raman spectroscopy. Vibrations related with Ba encaged in the Si cages are observed below 100  cm-1 by low-frequency Raman measurements of Ba8Si46 and Ba6.6Si46 clathrates. The high-pressure Raman spectra obtained for both compression and decompression processes reveal a new phase transition at 7 GPa, and the reversibility of the phase transition at 15 GPa. We investigate the mechanisms of these phase transitions, the interaction between the guest and host frame, and the volume dependence of the vibrational modes.


©2003 The American Physical Society

URL: http://link.aps.org/abstract/PRL/v90/e155503
DOI: 10.1103/PhysRevLett.90.155503
PACS: 63.20.Pw, 62.50.+p, 78.30.–j

* Electronic address: kume@cc.gifu-u.ac.jp

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