Issue
EPL
Volume 86, Number 5, June 2009
Article Number 56004
Number of page(s) 6
Section Condensed Matter: Structural, Mechanical and Thermal Properties
DOI http://dx.doi.org/10.1209/0295-5075/86/56004
Published online 19 June 2009
EPL, 86 (2009) 56004
DOI: 10.1209/0295-5075/86/56004

Glass-like thermal transport in symmetry-broken clathrates

E. Kaneshita1, 2 and T. Nakayama3, 4

1   Advanced Photon Source, Argonne National Laboratory - 9700 South Cass Avenue, Argonne, IL 60439, USA
2   Yukawa Institute for Theoretical Physics, Kyoto University - Kyoto 606-8502, Japan
3   Materials Science Division, Argonne National Laboratory - 9700 South Cass Avenue, Argonne, IL 60439, USA
4   Toyota Physical and Chemical Research Institute - Nagakute, Aichi 480-1192, Japan

knsht@yukawa.kyoto-u.ac.jp

received 20 January 2009; accepted in final form 20 May 2009; published June 2009
published online 19 June 2009

Abstract
We present the quantitative interpretation for the glass-like behavior of thermal conductivities $\kappa (T)$ for type-I clathrate compounds involving off-centered guest ions. It is shown that the dipole-dipole interaction generated in cage/guest-ion systems is crucial to reproduce the characteristics of thermal conductivities for these symmetry-broken clathrates. The above scenario also explains well the difference of $\kappa (T)$ between the p-type and the n-type $\beta $-BGS found recently by K. Suekuni et al. (Phys. Rev. B, 77 (2008) 235119.)

PACS
61.72.Bb - Theories and models of crystal defects.
66.35.+a - Quantum tunneling of defects.
61.43.-j - Disordered solids.

© EPLA 2009