Probing glasslike excitations in single-crystalline Sr8Ga16Ge30 by specific heat and thermal conductivity

被引：53

作者：

Umeo, K ^{[1
]}

Avila, MA

Sakata, T

Suekuni, K

Takabatake, T

机构：

[1] Hiroshima Univ, ADSM, Dept Quantum Matter, Higashihiroshima, Hiroshima 7398530, Japan

[2] Hiroshima Univ, NBARD, Ctr Mat Sci, Higashihiroshima, Hiroshima 7398530, Japan

来源：

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN | 2005年 / 74卷 / 08期

关键词：

Sr8Ga16Ge30; clathrate; specific heat; thermal conductivity; soft-potential model;

D O I：

10.1143/JPSJ.74.2145

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

We report the thermal conductivity K and specific heat C measurements down to 0.3 K on single-crystalline samples of n-type Sr8Ga16Ge30 and p-type Ba8Ga16Ge30 clathrates. The overall temperature dependence of K(T) of both samples with a plateau at about 20 K and a quadratic T dependence below I K is well described by the soft-potential model. Using the soft-potential parameter of 4.4 K derived from the analysis Of K(T) for Sr8Ga16Ge30, the broad maximum of C/T-3 centered at 7 K is also well reproduced. The density of states of quasilocalized vibrational modes for Sr atoms in Sr8Ga16Ge30 has a maximum at 0.7 THz, in agreement with the low-energy peak in a previous Raman scattering study.

引用

页码：2145 / 2148

页数：4

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