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Thermoelectric transport in Bi2Te3/Sb2Te3 superlattices

: Hinsche, N.F.; Yavorsky, B.Y.; Gradhand, M.; Czerner, M.; Winkler, M.; König, J.; Böttner, H.; Mertig, I.; Zahn, P.


Physical Review. B 86 (2012), No.8, Art.085323, 13 pp.
ISSN: 0163-1829
ISSN: 1098-0121
ISSN: 0556-2805
Journal Article
Fraunhofer IPM ()

The thermoelectric transport properties of Bi2Te3/Sb2Te3 superlattices are analyzed by means of first-principles calculations and semiclassical Boltzmann theory. The anisotropy of the thermoelectric transport under electron and hole doping was studied in detail for different superlattice periods at changing temperature and charge carrier concentrations. A clear preference for thermoelectric transport under hole doping, as well as for the in-plane transport direction was found for all superlattice periods. At hole doping the electrical transport anisotropies remain bulklike for all investigated systems, while under electron doping quantum confinement leads to strong suppression of the cross-plane thermoelectric transport at several superlattice periods. In addition, insights on the Lorenz function, the electronic contribution to the thermal conductivity, and the resulting figure of merit are given.