First-principles calculations to investigate effect of pressure on physical properties of LiNbO3 perovskite for photocatalytic application

Abstract

The present study explores the physical properties of LiNbO3 under pressure effect with the help of the CASTEP code with the GGA-PBE technique. The lattice parameters and volume lessen from 3.961 to 3.589 Å and 62.125 to 46.260 Å3, respectively, as the pressure rises from 0 to 100 GPa. The band gap varies from 1.684 to 2.284 eV because potential increases with rising pressure. The material possesses an indirect bandgap and is found mechanically stable, anisotropic, and ductile under the effect of pressure from 0 to 100 GPa. The material is found super hard from 0.0 to 20 GPa and ultra hard from 30 to 100 GPa, as predicted by Vickers hardness. Sharp peaks of reflectivity, absorption coefficient, and energy loss function are found in the UV region and exhibit an increasing trend with a slight shift towards higher energies. Lithium niobate is therefore an appropriate material for long-term photocatalytic activity in the UV range.