First-principles prediction of structural, mechanical and thermal properties of perovskite BaZrS3

The structural, mechanical and thermal properties of perovskite BaZrS3 have been investigated in terms of first-principles plane-wave pseudopotential method. Four structures such as GdFeO3-type, BaNiO3-type, NH4CdCl3-type and CaTiO3-type structures are considered. The results show that the calculated lattice structural results of perovskite BaZrS3 with the GdFeO3-type phase are in good agreement with the available experimental data. It is predicted that those structures are thermodynamically stable. The structural stability order of the four phases is GdFeO3-type > NH4CdCl3-type > CaTiO3-type > BaNiO3-type from the calculated formation energies. The elastic constants of the four structures prove that GdFeO3-type, NH4CdCl3-type and CaTiO3-type structures are mechanically stable while the BaNiO3-type structure is mechanically unstable. The mechanical properties of perovskite BaZrS3 such as the bulk modulus, shear modulus, Young's modulus and elastic anisotropy were calculated from the obtained elastic constants. The analysis of B/G ratio confirms that perovskite BaZrS3 is ductile materials. In particular, we firstly report the theoretical prediction of the thermal properties including Debye temperature and melting temperature of perovskite BaZrS3.