Anomalous infrared spectra of hybridized phonons in type-I clathrate Ba8Ga16Ge30

Kei Iwamoto, Shunsuke Kushibiki, Hironori Honda, Shuhei Kajitani, Tatsuya Mori, Hideki Matsumoto, Naoki Toyota, Koichiro Suekuni, Marcos A. Avila, Toshiro Takabatake

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8 Citations (Scopus)

Abstract

The optical conductivity spectra of the rattling phonons in the clathrate Ba8Ga16Ge30 are investigated in detail by use of the terahertz time-domain spectroscopy. The experiment has revealed that the lowest-lying vibrational mode of Ba(2)2+ ions consist of a sharp Lorentzian peak at 1.2 THz superimposed on a broad tail weighted in the lower frequency regime around 1.0 THz. With decreasing temperature, an unexpected linewidth broadening of the phonon peak is observed, together with monotonic softening of the phonon peak and enhancement of the tail structure. These observed anomalies are discussed in terms of impurity scattering effects on the hybridized phonon system of rattling and acoustic phonons.

Original languageEnglish
Article number024601
Journaljournal of the physical society of japan
Volume82
Issue number2
DOIs
Publication statusPublished - 2013 Feb 1

Keywords

  • Clathrates
  • Hybridized phonon system
  • Phonon-impurity interactions
  • Rattling phonons
  • THz time-domain spectroscopy

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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    Iwamoto, K., Kushibiki, S., Honda, H., Kajitani, S., Mori, T., Matsumoto, H., Toyota, N., Suekuni, K., Avila, M. A., & Takabatake, T. (2013). Anomalous infrared spectra of hybridized phonons in type-I clathrate Ba8Ga16Ge30. journal of the physical society of japan, 82(2), [024601]. https://doi.org/10.7566/JPSJ.82.024601