Regensburg 2013 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 13: Topical Session: Quasicrystals & Complex Metallic Alloys III

MM 13.6: Talk

Monday, March 11, 2013, 17:00–17:15, H25

Thermal Conductivity in Type-I Clathrate Systems — •Daniel Schopf and Hans-Rainer Trebin — Institut für Theoretische und Angewandte Physik, Universität Stuttgart

Intermetallic clathrates are currently actively investigated due to their special thermoelectric properties. They are composed of periodically arranged cages, formed by host atoms, which enclose single guest atoms. The low thermal conductivity of these structures has been attributed to the scattering of the phonons on the local vibration modes (``rattling'') of these guest atoms.

Molecular dynamics simulations can be used to study the influence of complexity on the thermal conductivity. To model the strongly directional atomic interactions in clathrates, angular dependent potentials are required. Effective potentials have been determined with the force-matching method and will be presented.

The Green-Kubo method has been used to calculate the thermal conductivity of clathrate systems with different levels of complexity. The influence of the size of the unit cell and the arrangement of vacancies as sources of the low conductivity are discussed.