Optical conductivity spectral anomalies in the off-center rattling system β-Ba 8 Ga 16 Sn 30

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

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Abstract

We present optical conductivity studies of the type-I clathrate Ba 8 Ga 16 Sn 30 , using a terahertz time-domain spectrometer (0.3-3.0 THz). The lowest-lying spectral peak at 0.72 THz due to the Ba(2) ion's off-center vibration in the oversized cage shows a drastic and anomalous temperature dependence. Below about 100 K, the single broad peak splits into two subpeaks, and with further lowering of the temperature, the spectral shape of this so-called rattling phonon shows non-Boltzmann broadening to the point that the linewidth becomes comparable to the peak frequency. Whereas the initial splitting can be understood by assuming a multiwell anharmonic potential, the strong linewidth broadening toward low temperature cannot, since the Boltzmann factor generally sharpens the low-temperature spectra. The observed behavior suggests strong interaction between the local anharmonic phonons and other excitations.

Original languageEnglish
Article number015501
JournalPhysical Review Letters
Volume106
Issue number1
DOIs
Publication statusPublished - Jan 17 2011

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anomalies
conductivity
clathrates
phonons
spectrometers
vibration
temperature dependence
excitation
ions
temperature

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

Cite this

Mori, T., Iwamoto, K., Kushibiki, S., Honda, H., Matsumoto, H., Toyota, N., ... Takabatake, T. (2011). Optical conductivity spectral anomalies in the off-center rattling system β-Ba 8 Ga 16 Sn 30 Physical Review Letters, 106(1), [015501]. https://doi.org/10.1103/PhysRevLett.106.015501

Optical conductivity spectral anomalies in the off-center rattling system β-Ba 8 Ga 16 Sn 30 . / Mori, T.; Iwamoto, K.; Kushibiki, S.; Honda, H.; Matsumoto, H.; Toyota, N.; Avila, M. A.; Suekuni, Koichiro; Takabatake, T.

In: Physical Review Letters, Vol. 106, No. 1, 015501, 17.01.2011.

Research output: Contribution to journalArticle

Mori, T, Iwamoto, K, Kushibiki, S, Honda, H, Matsumoto, H, Toyota, N, Avila, MA, Suekuni, K & Takabatake, T 2011, ' Optical conductivity spectral anomalies in the off-center rattling system β-Ba 8 Ga 16 Sn 30 ', Physical Review Letters, vol. 106, no. 1, 015501. https://doi.org/10.1103/PhysRevLett.106.015501
Mori, T. ; Iwamoto, K. ; Kushibiki, S. ; Honda, H. ; Matsumoto, H. ; Toyota, N. ; Avila, M. A. ; Suekuni, Koichiro ; Takabatake, T. / Optical conductivity spectral anomalies in the off-center rattling system β-Ba 8 Ga 16 Sn 30 In: Physical Review Letters. 2011 ; Vol. 106, No. 1.
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AU - Honda, H.

AU - Matsumoto, H.

AU - Toyota, N.

AU - Avila, M. A.

AU - Suekuni, Koichiro

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