Structural, elastic, thermodynamic, and electronic properties of BaHfO3: A first-principles study using GGA-PBEsol + TB-mBJ approach

Abstract

The structural, elastic, thermodynamic, and electronic properties of cubic perovskite BaHfO3 are calculated by means of the full-potential linearized augmented plane wave (FP-LAPW) method and the quasi-harmonic Debye model. Accurate structural and elastic parameters are obtained by using the GGA-PBEsol scheme of the generalized gradient approximation (GGA) to describe the exchange-correlation potential. BaHfO3 is found brittle, mechanically stable, and elastically anisotropic, with a predominance of directional bonding. First predictions of the Grüneisen parameter, the specific heat at constant volume, the isothermal bulk modulus, and the adiabatic bulk modulus are given. BaHfO3 has high thermal expansion coefficient. The effects of pressure and temperature on the thermodynamic parameters are also investigated. The electronic properties are calculated using the Tran-Blaha modified Becke-Johnson (TB-mBJ) exchange-correlation potential. BaHfO3 has an indirect band gap R-Γ of 5.66 eV. The top of the valence band is due essentially to O 2p states while the bottom of the conduction band results mainly from Ba d and Hf d t2g states. The Hf-O bonds have an iono-covalent character while the Ba-O bonds are ionic.