Phonon band structures and resonant scattering in and clathrates
Steacie Institute for Molecular Sciences,
National Research Council of Canada
Ottawa, Ontario, Canada K1A 0R6
Accepted: 26 July 2001
The low and glasslike thermal conductivity of metal-doped semiconductor clathrate compounds makes them potentially high-efficiency thermoelectric materials. The cause of this unique and remarkable property has been postulated to be due to resonant scattering of lattice phonons by localized vibrations of the dopants. We present theoretical evidence in support of this hypothesis through the analysis of electronic and vibrational interactions between dopant atoms with the host framework. In particular, the contrasting behavior of two clathrates: the glasslike thermal conductivity in and the normal behavior in can be rationalized.
PACS: 63.20.-e – Phonons in crystal lattices / 71.20.-b – Electron density of states and band structure of crystalline solids / 72.10.-d – Theory of electronic transport; scattering mechanisms
© EDP Sciences, 2001