Optical Properties and Electronic Band Structure of Topological Insulators on A25B36 compound based

We have performed a first principles study of structural, electronic, and optical properties of rhombohedral Sb2Te3 and Bi2Te3 compounds using the density functional theory within the local density approximation. The lattice parameters, bulk modulus, and its pressure derivatives of these compounds have been obtained. The linear photon-energy dependent dielectric functions and some optical properties such as the energy-loss function, the effective number of valance electrons and the effective optical dielectric constant are calculated and presented in the study