Bulk chalcogenides Bi2Te3 and Sb2Te3 as well as related heterostructures are well known to be efficient thermoelectric materials [1,2]. Recent research revealed Bi2Te3 and Sb2Te3 to be strong topological insulators, i.e. the bulk is insulating, while the surfaces are metallic due to the presence of robust gapless surface states . While the spin structure and the low-temperature electrical transport gained much attention, the physics of the thermoelectric transport is still under debate. To contribute on this, we studied the electronic structure of Sb2Te3 thin films with a fully relativistic screened Korringa-Kohn-Rostoker Green's function method. The thermoelectric transport properties were calculated within the relaxation time approximation of the Boltzmann theory. The influence of temperature, doping and film thickness on the thermoelectric transport were analyzed in detail and clear signatures of the surface state in the total thermoelectric transport can be revealed up to room temperature. Comparisons to Bi2Te3 thin films will be made .
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