Structural, elastic, and electronic properties of topological insulators: Sb<inf>2</inf>Te<inf>3</inf> and Bi<inf>2</inf>Te<inf>3</inf>

Abstract

We have performed a first principles study of structural, elastic, and electronic properties of rhombohedral Sb 2 Te 3 and Bi 2 Te 3 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 Sb 2 Te 3 and Bi 2 Te 3 compounds have a direct forbidden band gap. Our structural estimation and some other results are in agreement with the available experimental and theoretical data.