Optical conductivity of rattling phonons in type-I clathrate Ba8 Ga16 Ge30

T. Mori, S. Goshima, K. Iwamoto, S. Kushibiki, H. Matsumoto, N. Toyota, Koichiro Suekuni, M. A. Avila, T. Takabatake, T. Hasegawa, N. Ogita, M. Udagawa

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

A series of infrared-active optical phonons have been detected in type-I clathrate Ba8 Ga16 Ge30 by terahertz time-domain spectroscopy. The conductivity spectra with the lowest-lying peaks at 1.15 and 1.80 THz are identified with the so-called rattling phonons, i.e., optical modes of the guest ion Ba2+ (2) with T1u symmetry in the oversized tetrakaidecahedral cage. The temperature dependence of the spectra from these modes are totally consistent with calculations based on a one-dimensional anharmonic potential model that, with decreasing temperature, the shape becomes asymmetrically sharp associated with a softening for the weight to shift to lower frequency. These temperature dependences are determined, without any interaction effects, by the Bose factor for optical excitations of anharmonic phonons with the nonequally spaced energy levels.

Original languageEnglish
Article number212301
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume79
Issue number21
DOIs
Publication statusPublished - Jun 12 2009
Externally publishedYes

Fingerprint

Optical conductivity
clathrates
Phonons
phonons
conductivity
temperature dependence
Photoexcitation
softening
Temperature
Electron energy levels
energy levels
Spectroscopy
Ions
low frequencies
Infrared radiation
shift
symmetry
spectroscopy
excitation
ions

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

Mori, T., Goshima, S., Iwamoto, K., Kushibiki, S., Matsumoto, H., Toyota, N., ... Udagawa, M. (2009). Optical conductivity of rattling phonons in type-I clathrate Ba8 Ga16 Ge30. Physical Review B - Condensed Matter and Materials Physics, 79(21), [212301]. https://doi.org/10.1103/PhysRevB.79.212301

Optical conductivity of rattling phonons in type-I clathrate Ba8 Ga16 Ge30. / Mori, T.; Goshima, S.; Iwamoto, K.; Kushibiki, S.; Matsumoto, H.; Toyota, N.; Suekuni, Koichiro; Avila, M. A.; Takabatake, T.; Hasegawa, T.; Ogita, N.; Udagawa, M.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 79, No. 21, 212301, 12.06.2009.

Research output: Contribution to journalArticle

Mori, T, Goshima, S, Iwamoto, K, Kushibiki, S, Matsumoto, H, Toyota, N, Suekuni, K, Avila, MA, Takabatake, T, Hasegawa, T, Ogita, N & Udagawa, M 2009, 'Optical conductivity of rattling phonons in type-I clathrate Ba8 Ga16 Ge30', Physical Review B - Condensed Matter and Materials Physics, vol. 79, no. 21, 212301. https://doi.org/10.1103/PhysRevB.79.212301
Mori, T. ; Goshima, S. ; Iwamoto, K. ; Kushibiki, S. ; Matsumoto, H. ; Toyota, N. ; Suekuni, Koichiro ; Avila, M. A. ; Takabatake, T. ; Hasegawa, T. ; Ogita, N. ; Udagawa, M. / Optical conductivity of rattling phonons in type-I clathrate Ba8 Ga16 Ge30. In: Physical Review B - Condensed Matter and Materials Physics. 2009 ; Vol. 79, No. 21.
@article{ede2d7d8adf445fa8bf4224848dd2112,
title = "Optical conductivity of rattling phonons in type-I clathrate Ba8 Ga16 Ge30",
abstract = "A series of infrared-active optical phonons have been detected in type-I clathrate Ba8 Ga16 Ge30 by terahertz time-domain spectroscopy. The conductivity spectra with the lowest-lying peaks at 1.15 and 1.80 THz are identified with the so-called rattling phonons, i.e., optical modes of the guest ion Ba2+ (2) with T1u symmetry in the oversized tetrakaidecahedral cage. The temperature dependence of the spectra from these modes are totally consistent with calculations based on a one-dimensional anharmonic potential model that, with decreasing temperature, the shape becomes asymmetrically sharp associated with a softening for the weight to shift to lower frequency. These temperature dependences are determined, without any interaction effects, by the Bose factor for optical excitations of anharmonic phonons with the nonequally spaced energy levels.",
author = "T. Mori and S. Goshima and K. Iwamoto and S. Kushibiki and H. Matsumoto and N. Toyota and Koichiro Suekuni and Avila, {M. A.} and T. Takabatake and T. Hasegawa and N. Ogita and M. Udagawa",
year = "2009",
month = "6",
day = "12",
doi = "10.1103/PhysRevB.79.212301",
language = "English",
volume = "79",
journal = "Physical Review B - Condensed Matter and Materials Physics",
issn = "1098-0121",
publisher = "American Physical Society",
number = "21",

}

TY - JOUR

T1 - Optical conductivity of rattling phonons in type-I clathrate Ba8 Ga16 Ge30

AU - Mori, T.

AU - Goshima, S.

AU - Iwamoto, K.

AU - Kushibiki, S.

AU - Matsumoto, H.

AU - Toyota, N.

AU - Suekuni, Koichiro

AU - Avila, M. A.

AU - Takabatake, T.

AU - Hasegawa, T.

AU - Ogita, N.

AU - Udagawa, M.

PY - 2009/6/12

Y1 - 2009/6/12

N2 - A series of infrared-active optical phonons have been detected in type-I clathrate Ba8 Ga16 Ge30 by terahertz time-domain spectroscopy. The conductivity spectra with the lowest-lying peaks at 1.15 and 1.80 THz are identified with the so-called rattling phonons, i.e., optical modes of the guest ion Ba2+ (2) with T1u symmetry in the oversized tetrakaidecahedral cage. The temperature dependence of the spectra from these modes are totally consistent with calculations based on a one-dimensional anharmonic potential model that, with decreasing temperature, the shape becomes asymmetrically sharp associated with a softening for the weight to shift to lower frequency. These temperature dependences are determined, without any interaction effects, by the Bose factor for optical excitations of anharmonic phonons with the nonequally spaced energy levels.

AB - A series of infrared-active optical phonons have been detected in type-I clathrate Ba8 Ga16 Ge30 by terahertz time-domain spectroscopy. The conductivity spectra with the lowest-lying peaks at 1.15 and 1.80 THz are identified with the so-called rattling phonons, i.e., optical modes of the guest ion Ba2+ (2) with T1u symmetry in the oversized tetrakaidecahedral cage. The temperature dependence of the spectra from these modes are totally consistent with calculations based on a one-dimensional anharmonic potential model that, with decreasing temperature, the shape becomes asymmetrically sharp associated with a softening for the weight to shift to lower frequency. These temperature dependences are determined, without any interaction effects, by the Bose factor for optical excitations of anharmonic phonons with the nonequally spaced energy levels.

UR - http://www.scopus.com/inward/record.url?scp=67650096910&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=67650096910&partnerID=8YFLogxK

U2 - 10.1103/PhysRevB.79.212301

DO - 10.1103/PhysRevB.79.212301

M3 - Article

VL - 79

JO - Physical Review B - Condensed Matter and Materials Physics

JF - Physical Review B - Condensed Matter and Materials Physics

SN - 1098-0121

IS - 21

M1 - 212301

ER -