Guest ion motion in cage structure crystals investigated by Raman scattering

Masayuki Udagawa, Takumi Hasegawa, Yuichi Takasu, Norio Ogita, Koichiro Suekuni, Marcos A. Avila, Toshiro Takabatake, Yoshikazu Ishikawa, Naoya Takeda, Yuichi Nemoto, Terutaka Goto, Hitoshi Sugawara, Daisuke Kikuchi, Hideyuki Sato, Chihiro Sekine, Ichimin Shirotani, Jun Ichi Yamaura, Yohei Nagao, Zenji Hiroi

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


Last five years we have mainly investigated phonons in the following cage compounds by Raman scattering: RT4X12, A 8Ga16Ge30, La3Pd20Ge 6, RB6, KOs2O6. From this systematic investigation we have clarified the following dynamical properties of the guest ion trapped in the large cages. The vibration of the guest ion is highly anharmonic due to weak atomic interaction between the guest ion and cage atom. This anharmonicity universally decreases the vibration energy of the guest ion with decreasing temperature. The existence of carriers decreases the interaction between the guest atoms and changes the dispersion curve of the guest ion mode to flat, which is the experimental evidence of the weak interaction between the guest atoms. For thermoelectricity, it is found in A8Ga 16Ge30 that the off-center rattling decreases lattice thermal conductivity.

Original languageEnglish
Pages (from-to)142-147
Number of pages6
Journaljournal of the physical society of japan
Issue numberSUPPL.A
Publication statusPublished - 2008
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy


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