Glasslike versus crystalline thermal conductivity in carrier-tuned Ba8 Ga16 X30 clathrates (X=Ge,Sn)

M. A. Avila, K. Suekuni, K. Umeo, H. Fukuoka, S. Yamanaka, T. Takabatake

Research output: Contribution to journalArticle

112 Citations (Scopus)

Abstract

The present controversy over the origin of glasslike thermal conductivity observed in certain crystalline materials is addressed by studies on single-crystal x-ray diffraction, thermal conductivity κ (T), and specific heat Cp (T) of carrier-tuned Ba8 Ga16 X30 (X=Ge,Sn) clathrates. These crystals show radically different low-temperature κ (T) behaviors depending on whether their charge carriers are electrons or holes, displaying the usual crystalline peak in the former case and an anomalous glasslike plateau in the latter. In contrast, Cp (T) above 4 K and the general structural properties are essentially insensitive to carrier tuning. We analyze these combined results within the framework of tunneling scattering, resonant scattering, and Rayleigh scattering models, and conclude that the evolution from crystalline to glasslike κ (T) is accompanied by an increase both in the effective density of tunneling states and in the resonant scattering level, while neither one of these contributions can solely account for the observed changes in the full temperature range. This suggests that the most relevant factor that determines crystalline or glasslike behavior is the coupling strength between the guest vibrational modes and the frameworks with different charge carriers.

Original languageEnglish
Article number125109
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume74
Issue number12
DOIs
Publication statusPublished - Sep 25 2006

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clathrates
Thermal conductivity
thermal conductivity
Crystalline materials
charge carriers
Scattering
Charge carriers
scattering
Rayleigh scattering
vibration mode
plateaus
x ray diffraction
tuning
specific heat
Specific heat
Structural properties
Tuning
Diffraction
single crystals
Single crystals

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

Glasslike versus crystalline thermal conductivity in carrier-tuned Ba8 Ga16 X30 clathrates (X=Ge,Sn). / Avila, M. A.; Suekuni, K.; Umeo, K.; Fukuoka, H.; Yamanaka, S.; Takabatake, T.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 74, No. 12, 125109, 25.09.2006.

Research output: Contribution to journalArticle

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