First Principles Studies on the Electronic Structure and Band Structure of Paraelectric SrTiO₃ by Different Approximations

Abstract

The electronic structure, energy band structure, total density of states (DOS) and electronic density of perovskite SrTiO₃ in the cubic phase are calculated by the using full potential-linearized augmented plane wave (FP-LAPW) method in the framework density functional theory (DFT) with the generalized gradient approximation (GGA) by WIEN2k package. The calculated band structure shows a direct band gap of 2.5 eV at the Γ point in the Brillouin zone.The total DOS is compared with experimental x-ray photoemission spectra. From the DOS analysis, as well as charge-density studies, I have conclude that the bonding between Sr and TiO₂ is mainly ionic and that the TiO₂ entities bond covalently.The calculated band structure and density of state of SrTiO₃ are in good agreement with theoretical and experimental results.