First principles study of the structural and electronic properties of double perovskite Ba2YTaO6 in cubic and tetragonal phases

The Ba2YTaO6 double perovskite presents a transition from cubic (Fm-3m) to tetragonal structure (14/m) at high temperature. In this work, we present a detailed study of the structural and electronic properties of the double perovskite Ba2YTaO6 in space group Fm-3m and 14/m. Calculations were made with the Full-Potential Linear Augmented Plane Wave method (FP-LAPW) within the framework of the Density Functional Theory (DFT) with exchange and correlation effects in the Generalized Gradient (GGA) and Local Density (LDA) approximations. From the minimization of energy as a function of volume and the fitting of the Murnaghan equation some structural characteristics were determined as, for example, total energy, lattice parameter (a=8.50 angstrom in cubic phase and a=5.985 angstrom and c=8.576 angstrom in tetragonal), bulk modulus (135.6 GPa in cubic phase and 134.1 GPa in tetragonal phase) and its derivative. The study of the electronic characteristics was performed from the analysis of the electronic density of states (DOS). We Find a non-metallic behavior for this with a direct band gap of approximately 3.5 eV and we found that the Ba2YTaO6 (14/m) phase is the most stable one. (C) 2013 Elsevier Science. All rights reserved. (C) 2014 Elsevier B.V. All rights reserved.