Hybrid-Density Functional Theory Study on Band Structures of Tetradymite-Bi2Te3, Sb2Te3, Bi2Se3, and Sb2Se3 Thermoelectric Materials

摘要

The low energy band structure near the band gap determines the electricalperformance of thermoelectric materials. Here, by using the hybrid-densityfunctional theory (hybrid-DFT) calculations, we calculate the low energy bandstructure of Bi2Te3, Sb2Te3, Bi2Se3 and Sb2Se3 in tetradymite phase. We findthat the band structure characteristics are very sensitive the selection of theexchange energy functional. The predictability of the band gaps and banddegeneracies is not enhanced in hybrid-DFT calculations, as compared to DFTcalculations. The poor prediction of low energy band structures is originatedfrom the poor prediction of interlayer distances and the high structuresensitivity on the band gap. We conclude that the hybrid DFT calculations arenot superior to DFT calculations when predicting band structures of tetradymiteBi2Te3, Sb2Te3, Bi2Se3 and Sb2Se3 thermoelectric materials.