Theoretical study of electronic structures of Bi₂Te ₃/Sb₂Te₃ superlattices

To understand thermoelectric properties of multiplayer Bi ₂Te₃ /Sb₂Te₃ superlattices, especially their charge transport properties, electronic structure calculations were carried out using ab-initio gradient corrected density functional theory. The superlattice structures of (1,1) and (1,2) Bi₂Te ₃/Sb₂Te₃ multilayers were optimized and their band structures were compared with each other. Different lattice relaxation effects are observed for the two structures. The cross-plane and in-plane effective masses for both these systems are found to be comparable, consistent with experimental mobility measurements.