Complex Band Structures and Lattice Dynamics of Bi2Te3-Based Compounds and Solid Solutions

Bi2Te3-based compounds and derivatives are milestone materials in the fields of thermoelectrics (TEs) and topological insulators (TIs). They have highly complex band structures and interesting lattice dynamics, which are favorable for high TE performance as well as strong spin orbit and band inversion underlying topological physics. This review presents rational calculations of properties related to TEs and provides theoretical guidance for improving the TE performance of Bi2Te3-based materials. Although the band structures of these TE materials have been studied theoretically and experimentally for many years, there remain many controversies on band characteristics, especially the locations of band extrema and the exact values of bandgaps. Here, the key factors in the theoretical investigations of Bi2Te3, Bi2Se3, Sb2Te3, and their solid solutions are reviewed. The phonon spectra and lattice thermal conductivities of Bi2Te3-based materials are discussed. Electronic and phonon structures and TE transport calculations are discussed and reported in the context of better establishing computational parameters for these V2VI3-based materials. This review provides a useful guidance for analyzing and improving TE performance of Bi2Te3-based materials.