Phase stability, band gap engineering and optical response of Li-, Be- and Mg-doped SrZrO3 perovskite: Theoretical perspective with GGA-PBE

A detailed computational perspective, with CASTEP package having exchange correlation function GGA-PBE and USP (ultra-soft pseudopotential), to explore the structural stability, bandgap engineering and optical properties of beryllium (Be)-, magnesium (Mg)- and lithium (Li)-doped SrZrO3 is presented. The results of structural properties of SrZrO3 reveal that the partial replacement of Sr atoms with Li, Be and Mg atoms leads to decrease in lattice constants and hence volume of the unit cell. This decrease in lattice constants effects the electronic band structure and it decreases, after the doping of Mg and Be, from 3.313 to 1.863 eV and 0.906 eV, respectively. But after the doping of Li atoms, the increase in band gap (3.438 eV) is observed due to its strong polarization strength and limited scale. The nature of the band gap is changed from indirect to direct with Li-doping and remains same for Mg- and Be-doping and reason of band gap engineering is explained with PDOS, TDOS and elemental PDOS. The optical properties of pure and doped SrZrO3 are correlated with their electronic properties. The performance of modified electronic and optical properties of SrZrO3 after doping of Li, Be and Mg metals would be suitable in optoelectronic devices.