First-principles investigation of structural, electronic, optical and thermal properties of Zinc doped SrTiO₃

This work reports the first-principles study, based on the density functional theory (DFT), by using generalized gradient approximation (GGA) and ultra-soft pseudo-potential (USP), to explore effects of zinc (Zn) doping on structural, electronic, optical and thermal properties of cuboctahedral SrTiO₃. We observe significant reduction in unit cell volume upon doping Zn into SrTiO₃. Furthermore, Zn doping introduces new sates at Brillouin zone symmetry points turning the indirect band gap of host material into direct one. Replacement of Zn with Sr in host lattice repositions density of states at lower energies resulting in stronger interactions between Zn-atom and its neighbors as compared to interactions between Sr-atom and its surroundings. This refers to substantial modification in electronic band structure of host material by Zn doping. Physical properties of SrTiO₃ also change significantly upon Zn doping in accordance with the electronic band structure. Significant changes in electronic structure and properties of SrTiO₃ by Zn doping opens new prospects for potential applications of these materials in optoelectronics.