Abstract
The full-potential linearized augmented plane waves (FP-LAPW) method based the on density functional theory (DFT) using the generalized gradient approximation (GGA) is applied to study the structural, mechanical, and electronic properties of BaTiO3, BaZrO3, and BaNbO3 cubic perovskites. The quasi-harmonic Debye model, by means of total energy versus volume calculations obtained with the FP-LAPW method, is applied to study the thermal and vibrational effects. Predicted temperature and pressure effects on the structural parameters, thermal expansions, heat capacities, and Debye temperatures are determined from the non-equilibrium Gibbs functions.