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ID 31971
本文ファイル
著者
Mori, Tatsuya
Iwamoto, K.
Kushibiki, S.
Honda, H.
Matsumoto, Hideki
Toyota, Naoki
Avila, ​Marcos A.
NDC
物理学
内容記述
We present optical conductivity studies of the type-I clathrate Ba_8Ga_<16>Sn_<30>, using a terahertz time-domain spectrometer (0.3-3.0 THz). The lowest-lying spectral peak at 0.72 THz due to the Ba(2) ion's off-center vibration in the oversized cage shows a drastic and anomalous temperature dependence. Below about 100 K, the single broad peak splits into two subpeaks, and with further lowering of the temperature, the spectral shape of this so-called rattling phonon shows non-Boltzmann broadening to the point that the linewidth becomes comparable to the peak frequency. Whereas the initial splitting can be understood by assuming a multiwell anharmonic potential, the strong linewidth broadening toward low temperature cannot, since the Boltzmann factor generally sharpens the low-temperature spectra. The observed behavior suggests strong interaction between the local anharmonic phonons and other excitations.
掲載誌名
Physical review letters
106巻
1号
開始ページ
015501-1
終了ページ
015501-4
出版年月日
2011-01-06
出版者
The American Physical Society
ISSN
0031-9007
NCID
出版者DOI
言語
英語
NII資源タイプ
学術雑誌論文
広大資料タイプ
学術雑誌論文
DCMIタイプ
text
フォーマット
application/pdf
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権利情報
Copyright (c) 2011 The American Physical Society
関連情報URL
部局名
先端物質科学研究科