High-throughput first-principle calculations of the structural, mechanical, and electronic properties of cubic XTiO3 (X = Ca, Sr, Ba, Pb) ceramics under high pressure

摘要

High-throughput first-principle calculations are implemented to study the structural, mechanical, and electronic properties of cubic XTiO3 (X = Ca, Sr, Ba, Pb) ceramics under high pressure. The effects of applied pressure on physical parameters, such as elastic constants, bulk modulus, Young's modulus, shear modulus, ductile-brittle transition, elastic anisotropy, Poisson's ratio, and band gap, are investigated. Results indicate that high pressure improves the resistance to bulk, elastic, and shear deformation for XTiO3 ceramics. Pugh's ratios B/G reveal that CaTiO3 and PbTiO3 ceramics are ductile, but SrTiO3 and BaTiO3 ceramics are brittle under the ground state. The brittle-to-ductile transition pressures are 24.26 GPa for SrTiO3 and 43.23 GPa for BaTiO3. Under high pressure, the strong anisotropy promotes the cross-slip process of screw dislocations, and then enhances the plasticity of XTiO3 ceramics. Meanwhile, XTiO3 (X = Ca, Sr, Ba) is intrinsically an indirect-gap ceramic, but PbTiO3 is a direct-gap ceramic. High pressure increases the band gap of XTiO3 (X = Ca, Sr, Ba) ceramic, but decreases that of PbTiO3 ceramic. This work is helpful for designing and applying XTiO3 ceramics under high pressure.