Structural, elastic, and electronic properties of topological insulators: Sb2Te3 and Bi2Te3

We have performed a first principles study of structural, elastic, and electronic properties of rhombohedral Sb₂Te₃ and Bi₂Te₃ compounds using the density functional theory within the local density approximation. The lattice parameters of considered compounds have been calculated. The second-order elastic constants have been calculated, and the other related quantities such as the Young´s modulus, shear modulus, Poisson´s ratio, anisotropy factor, sound velocities, and Debye temperature have also been estimated in the present work. The calculated electronic band structure shows that Sb₂Te₃ and Bi₂Te₃ compounds have a direct forbidden band gap. Our structural estimation and some other results are in agreement with the available experimental and theoretical data.