Universal relation between guest free space and lattice thermal conductivity reduction by anharmonic rattling in type-I clathrates

Kouichirou Suekuni, Shuhei Yamamoto, Marcos A. Avila, Toshiro Takabatake

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Since the early days of studies on thermoelectric clathrates it has been evidenced that the lowering of thermal conductivity in these compounds is related to the guest ion's rattling characteristics. Here we report on the relation between the guest vibration and lattice thermal conductivity κL in single crystalline samples of type-I clathrates Ba 8In16Ge30-xMx (M = Si, Sn) with n-type carriers. On going from Mx = Si1.6 to Mx = Sn2.2, the lattice parameter increases by 1% from 11.20 to 11.30 Å. This is accompanied by a decrease from 39 K to 35 K in the local vibration energy of the Ba guest ions in the tetrakaidecahedron cages, and a strong suppression of κL, which shows glasslike temperature dependence for Mx = Sn2.2. We further demonstrate that the lowering of κL at 150 K shows universality behavior and scales very well with the guest free space for vibration in all type-I clathrates, largely independent of the guest or framework ions.

Original languageEnglish
Pages (from-to)61-66
Number of pages6
Journaljournal of the physical society of japan
Volume77
Issue numberSUPPL.A
DOIs
Publication statusPublished - Jan 1 2008
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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