Optical conductivity of rattling phonons in type-I clathrates Ba 8Ga 16Ge 30 and Ba 8Ga 16Sn 30

K. Iwamoto, T. Mori, S. Kushibiki, H. Honda, H. Matsumoto, K. Suekuni, M. A. Avila, T. Takabatake, N. Toyota

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)

Abstract

We review our dynamical property measurements of rattling phonons in type-I clathrate compounds, the quasi-on-center Ba 8Ga 16Ge 30 (BGG) and off-center Ba 8Ga 16Sn 30 (BGS), using a terahertz time-domain spectrometer. The lowest-lying vibrational modes of rattling Ba ions in the oversized cage show anomalous temperature dependence in their spectra. For BGG, the temperature dependence is mostly consistent with a local anharmonic potential approximation that predicts softening towards low temperature. On the other hand, for BGS, a single broad peak of off-center rattling phonons splits into two subpeaks below 120 K, and, with further lowering temperature, the spectra show anomalous broadening. While the splitting can be understood by the double well potential, the linewidth broadening must be attributed to some relevant interactions with such excitations as acoustic phonons and doped carriers.

Original languageEnglish
Title of host publicationMaterials Integration
Pages341-346
Number of pages6
DOIs
Publication statusPublished - Apr 18 2012
Externally publishedYes
EventInt. Symposium of GCOE: Materials Integration, in Conjunction with the 2nd Int. Symposium on Advanced Synthesis and Processing Technology for Materials, ASPT 2011 and the 8th Materials Science School for Young Scientists, KINKEN-WAKATE 2011 - Sendai, Japan
Duration: Dec 1 2011Dec 2 2011

Publication series

NameKey Engineering Materials
Volume508
ISSN (Print)1013-9826

Other

OtherInt. Symposium of GCOE: Materials Integration, in Conjunction with the 2nd Int. Symposium on Advanced Synthesis and Processing Technology for Materials, ASPT 2011 and the 8th Materials Science School for Young Scientists, KINKEN-WAKATE 2011
CountryJapan
CitySendai
Period12/1/1112/2/11

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

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    Iwamoto, K., Mori, T., Kushibiki, S., Honda, H., Matsumoto, H., Suekuni, K., Avila, M. A., Takabatake, T., & Toyota, N. (2012). Optical conductivity of rattling phonons in type-I clathrates Ba 8Ga 16Ge 30 and Ba 8Ga 16Sn 30 In Materials Integration (pp. 341-346). (Key Engineering Materials; Vol. 508). https://doi.org/10.4028/www.scientific.net/KEM.508.341