Bandgap tuning with pressure for plausible piezoelectric and electronic applications of Lanthanum oxides LaMO3 (M = Al, Ga, Ti and V)

Abstract

In this article, we have used density functional theory to investigate the pressure dependent structural, elastic, thermal and electronic properties of LaMO3 (M = Al, Ga, Ti and V) compounds. Optimized structural attributes suggest all compounds are thermodynamically stable based on enthalpy of formation, ground state optimizations and tolerance factor. Moreover, elastic stability criteria also portray results in support of the structural stability of compounds. In electronic properties, the density of states plot suggests anti-ferromagnetic attributes. While transition in the band gap from indirect to direct is observed at 50 GPa for all studied compounds except for LaGaO3. In mechanical properties, stiffness, super-plasticity and moduli of elasticity of the studied compounds observed to increase linearly with pressure. The compound LaTiO3 has shown plausible piezoelectricity under pressure. We expect that studied compounds will fulfil requirements of high pressure optoelectronic sensors and devices.