Computational study of Be doped LaAlO3 perovskite

Abstract

DFT based calculations are used to study the structural and elastic properties of pure and doped LaAlO3. By inclusion Be along La-site and Al-site (La1-xBexAlO3 and LaAl1-x BexO3, x = 0%, 20%, 40%, 60%, 80% and 100%) LaAlO3 structure are investigated. The effect of Be doping along with La-site and Al-sites was studied using supercell calculation. The structural properties show a change in the lattice parameter because of Be doping. Our results show that after doping Be the nature and magnitude of band structure are affected significantly. Be doping along La-sites the band structure diagram shows valence band and conduction band are overlapped indicating metallic conductivity of doped material. While for Be doping along with Al-sites the band gap increases from 3.01 eV to 3.31 eV, also, the nature of the band gap changes from indirect to direct band gap. By studying the elastic constant, bulk moduli, shear moduli, Young's moduli, Poisson's ratio, Pugh's ratio and Cauchy pressure we concluded that by Be doping, the structure is mechanically stable and more ductile. The study of mean sound velocity and Debye temperature shows that the under-discussion material has weaker bonding and lower thermal conductivity than the pure LaAlO3. The inclusion of Be atoms along La-sites and Al-sites of LaAlO3 structure significantly shakes up the properties of the selected material and make it compatible material for a vast range of applications. We also considered the pressure induced structural properties of pure LaAlO3 and Be doped LaAlO3.