Alteration impact of electronic properties of c-SrTiO3 on optical response due to Ca inclusion: A DFT study

Abstract

In present study, calcium (Ca) is used as a dopant to explore the optical properties of cubic SrTiO3 through first principles calculation. To execute the calculations, GGA and ultra-soft pseudo potential were used. The minimal impact of impurity inclusion was studied. Thus only two atoms of Ca were doped at Sr sites in intrinsic SrTiO3. The purpose of this work was to determine the impact of Ca inclusion due to modification in electronic properties. Due to the emergence of new states the band gap was reduced from 1.821eV to 1.783eV. The appearance of new states was observed in density of states graphs. The s-state of Ca played a vigorous role in alteration of system's overall behavior. This impact was directly affecting the optical response of the system and a red shift was observed as the absorption edge shifted towards lower energy region. Refractive index was reduced from 7.3 to 3.6, thus making it more transparent. Other calculated optical properties are complex dielectric function, absorption, energy lose function, reflectivity and extinction coefficient. Calcium doping surely affects the electronic property of SrTiO3 which changes the optical response of the said material. Thus Ca doped SrTiO3 is a valuable addition in optoelectronic materials.