Structural and response properties of all BaTiO3 phases from density functional theory using the projector-augmented-wave methods

Abstract

A study of ground state properties of bulk BaTiO3 perovskite crystal was conducted using first-principles density functional theory with local-density approximation (LDA) and generalized-gradient approximation (GGA), using the projector-augmented wave methods. Two different PAW potentials developed by Jollet–Torrent–Holzwarth (JTH) and Garrity–Bennett–Rabe–Vanderbilt (GBRV) are employed in the calculations. This study emphasize on electronic, structural and response properties of all BaTiO3 phases using different exchange correlation (XC) functionals and PAW potentials. Lattice parameters, cohesion energy, bulk modulus, Born effective charge, spontaneous polarization and charge densities of all BaTiO3 phases are calculated. In addition, gamma point phonon frequencies are computed with LDA. Structural and vibrational properties predicted using the two PAW potentials are consistent with experimental and previous theoretical studies for all BaTiO3 phases. It is observed that calculations with GGA yields structural properties much closer to reported experimental values than LDA. Spontaneous polarization computed using Berry phase approach for the three structures in ferroelectric phase are consistent with other theoretical results, but differ considerably from experimental values. The deviation of lattice parameters computed using different XC functionals directly affects the computed spontaneous polarization. An analysis of phonon mode symmetries and frequencies conformed to experimental findings in the literature.