Structural, electronic and optical properties of copper-doped SrTiO₃ perovskite: A DFT study

First-principles calculations based on the density function theory (DFT) are implemented to explore the effect of Cu doping on the structural, electronic and optical properties of SrTiO₃ Perovskite using generalized gradient approximation (GGA) and ultrasoft pseudo-potential (USP). The effects of Cu doping on the formation energy, electronic structure and optical property are discussed here. The results of formation energies infer that Cu doping at Sr site in SrTiO₃ is more favorable as compared to Ti site. Cu incorporation at Sr site affects the electronic band structure of SrTiO₃ significantly by introducing new states at Gamma point consequently transforming its indirect band gap into the direct one. The relocation of density of states to lower energies, and an increased interaction between Cu atom and its neighboring atoms after Cu doping in SrTiO₃ are observed. Furthermore, the partial density of states of SrTiO₃ changes significantly at the bottom of conduction band and hence we conclude that the Cu doping affects the electronic band structure of SrTiO₃. Cu doped SrTiO₃ offers enhanced optical properties and its conversion to direct band gap makes it an appealing candidate for optoelectronic devices.