Low-temperature heat capacity of Sr8Ga16Ge30 and Ba8Ga16Ge30: Tunneling states and electron-phonon interaction in clathrates

被引：29

作者：

Xu, Jingtao ^{[1
]}

Tang, Jun ^{[1
]}

Sato, Kazumi ^{[2
]}

Tanabe, Yoichi ^{[1
]}

Miyasaka, Hitoshi ^{[3
]}

Yamashita, Masahiro ^{[3
]}

Heguri, Satoshi ^{[2
]}

Tanigaki, Katsumi ^{[1
,2
]}

机构：

[1] Tohoku Univ, WPI AIMR, Aoba Ku, Sendai, Miyagi 9808578, Japan

[2] Tohoku Univ, Grad Sch Sci, Dept Phys, Aoba Ku, Sendai, Miyagi 9808578, Japan

[3] Tohoku Univ, Grad Sch Sci, Dept Chem, Aoba Ku, Sendai, Miyagi 9808578, Japan

来源：

PHYSICAL REVIEW B | 2010年 / 82卷 / 08期

关键词：

THERMOELECTRIC PROPERTIES; THERMAL-CONDUCTIVITY; SINGLE-CRYSTALLINE; N-TYPE;

D O I：

10.1103/PhysRevB.82.085206

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

Tunneling states of Sr8Ga16Ge30 (SGG) and Ba8Ga16Ge30 (BGG) are studied in detail using single crystals with a variety of carrier concentrations from the view point of heat capacity (C-p). An important excessive contribution alpha T due to the tunneling states is found besides gamma T-e of the conduction electrons. The value of alpha is accurately deduced to be 10.1 +/- 1.5 mJ/mol K-2 for SGG while such a value is as small as 0.8 +/- 0.4 mJ/mol K-2 for BGG. From the temperature evolution of C-p as a function of carrier concentration, the effective masses, one of the most important physical parameters for evaluating electron-phonon interactions lambda(e-ph), are accurately estimated to be 1.68m(0) and 1.01m(0) for SGG and BGG, respectively. The lambda(e-ph) seems to be enhanced when the anharmonic rattling modes are involved.

引用

页数：5

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