Screened exchange LDA determination of the ground and excited state properties of thermoelectrics: Bi2Te3

Predicting the performance of thermoelectric materials requires precise knowledge of the Fermi surface and near-lying electronic structures. While Bi2Te3 is a major constituent of the active layers in commercial thermoelectric coolers, ab initio electronic structure theory heretofore has failed to reproduce the measured experimental band gap. Herein, we report self-consistent screened-exchange local density approximation (sX-LDA) calculations for the electronic structure of Bi2Te3, using the precise full-potential linearized augmented plane-wave method including self-consistent spin-orbit coupling. Our results include (i) a predicted sX-LDA band gap of 154meV, in excellent agreement with the zero temperature extrapolated experimental value of 162meV; this value may be compared with previously reported LDA and generalized gradient approximation values of 61 and 50meV, respectively; and (ii) significant improvement in the effective masses of electrons, with respect to experiments and previous calculations.