Electronic structure of β-As2Te3

We present calculations of the electronic structure of Bi2Te3-structure type (R3̄m) β-As2Te3 using the state-of-the-art full potential linearized augmented plane wave method implemented in the WIEN2K code. Bi2Te3–structure type arsenic telluride, which forms when monoclinic arsenic telluride is quenched from high temperatures or compressed, is found to be a direct gap semiconductor with εg=0.12 eV. We also calculated the electronic structure of Bi2Te3 using the same method for comparison. In contrast to earlier calculations, we optimized the lattice parameters within density functional theory. The lowest conduction band and highest valence band of β-As2Te3 are similar to those of Bi2Te3 over much of the Brillouin zone, but exhibit a modest difference at the Γ point. β-As2Te3 will likely have a large thermoelectric power in view of its similarity to Bi2Te3, including the presence of six-fold degenerate band edges.