Abstract
We report on thermoelectric and Raman scattering studies of single crystalline samples of a type I clathrate Ba 8Ga 16Sn 30. The n- and p-type samples have a thermopower of -300 μV/K and +270 μV/K, and electrical resistivity of 20 mΩ cm and 40 mΩ cm at room temperature, respectively. Regardless of the charge carrier type, the lattice thermal conductivity κ L shows typical glass-like behavior. The low-energy vibration of Ba(2) in the tetrakaidecahedron is manifested in the Raman scattering spectrum as a peak at 15 cm -1. This energy agrees with the characteristic vibrational temperature of 20 K derived from the analysis of the specific heat data with a soft-potential model. The fact that both the vibrational energy and the magnitude of κ L for Ba 8Ga 16Sn 30 are lowest among the type I clathrates is evidence that off-center vibrations are responsible for the strong reduction of κ L. Analysis of κ L(T) revealed that the positional disorder associated with the off-center vibrations acts as the Rayleigh scattering center, and the coupling between guest vibrational modes and acoustic phonons is stronger than that in Sr 8Ga 16Ge 30 and Eu 8Ga 16Ge 30.
| Original language | English |
|---|---|
| Pages (from-to) | 1516-1520 |
| Number of pages | 5 |
| Journal | Journal of Electronic Materials |
| Volume | 38 |
| Issue number | 7 |
| DOIs | |
| Publication status | Published - Jul 1 2009 |
| Externally published | Yes |
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All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering
- Materials Chemistry
Cite this
Off-center guest vibrations and their effect on lattice thermal conductivity in n- and p-type β-Ba 8Ga 16Sn 30 . / Suekuni, Koichiro; Tanaka, Tomoo; Yamamoto, Shuhei; Avila, Marcos A.; Umeo, Kazunori; Takasu, Yuichi; Hasegawa, Takumi; Ogita, Norio; Udagawa, Masayuki; Takabatake, Toshiro.
In: Journal of Electronic Materials, Vol. 38, No. 7, 01.07.2009, p. 1516-1520.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Off-center guest vibrations and their effect on lattice thermal conductivity in n- and p-type β-Ba 8Ga 16Sn 30
AU - Suekuni, Koichiro
AU - Tanaka, Tomoo
AU - Yamamoto, Shuhei
AU - Avila, Marcos A.
AU - Umeo, Kazunori
AU - Takasu, Yuichi
AU - Hasegawa, Takumi
AU - Ogita, Norio
AU - Udagawa, Masayuki
AU - Takabatake, Toshiro
PY - 2009/7/1
Y1 - 2009/7/1
N2 - We report on thermoelectric and Raman scattering studies of single crystalline samples of a type I clathrate Ba 8Ga 16Sn 30. The n- and p-type samples have a thermopower of -300 μV/K and +270 μV/K, and electrical resistivity of 20 mΩ cm and 40 mΩ cm at room temperature, respectively. Regardless of the charge carrier type, the lattice thermal conductivity κ L shows typical glass-like behavior. The low-energy vibration of Ba(2) in the tetrakaidecahedron is manifested in the Raman scattering spectrum as a peak at 15 cm -1. This energy agrees with the characteristic vibrational temperature of 20 K derived from the analysis of the specific heat data with a soft-potential model. The fact that both the vibrational energy and the magnitude of κ L for Ba 8Ga 16Sn 30 are lowest among the type I clathrates is evidence that off-center vibrations are responsible for the strong reduction of κ L. Analysis of κ L(T) revealed that the positional disorder associated with the off-center vibrations acts as the Rayleigh scattering center, and the coupling between guest vibrational modes and acoustic phonons is stronger than that in Sr 8Ga 16Ge 30 and Eu 8Ga 16Ge 30.
AB - We report on thermoelectric and Raman scattering studies of single crystalline samples of a type I clathrate Ba 8Ga 16Sn 30. The n- and p-type samples have a thermopower of -300 μV/K and +270 μV/K, and electrical resistivity of 20 mΩ cm and 40 mΩ cm at room temperature, respectively. Regardless of the charge carrier type, the lattice thermal conductivity κ L shows typical glass-like behavior. The low-energy vibration of Ba(2) in the tetrakaidecahedron is manifested in the Raman scattering spectrum as a peak at 15 cm -1. This energy agrees with the characteristic vibrational temperature of 20 K derived from the analysis of the specific heat data with a soft-potential model. The fact that both the vibrational energy and the magnitude of κ L for Ba 8Ga 16Sn 30 are lowest among the type I clathrates is evidence that off-center vibrations are responsible for the strong reduction of κ L. Analysis of κ L(T) revealed that the positional disorder associated with the off-center vibrations acts as the Rayleigh scattering center, and the coupling between guest vibrational modes and acoustic phonons is stronger than that in Sr 8Ga 16Ge 30 and Eu 8Ga 16Ge 30.
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U2 - 10.1007/s11664-009-0686-6
DO - 10.1007/s11664-009-0686-6
M3 - Article
AN - SCOPUS:67650489046
VL - 38
SP - 1516
EP - 1520
JO - Journal of Electronic Materials
JF - Journal of Electronic Materials
SN - 0361-5235
IS - 7
ER -