Electronic and optical properties of SrTiO3 under pressure effect: Ab initio study

• The effect of the cubic–tetragonal phase transition on the electronic and optical properties of SrTiO3.
• The band structure, densities of states and charge densities in the two phases.
• Discussion for electronic and optical properties at the Γ and R points in the Brillouin zone.
• The dielectric function and the refractive index are calculated between 0 and 45 eV.
• The extinction coefficient and the reflectivity spectrum are calculated between 0 and 45 eV.

We present an investigation on hydrostatic pressure dependence of electronic and optical properties of the perovskite SrTiO3 in cubic and tetragonal structures, including band structure, density of states, dielectric function, refractive index, absorption coefficient, reflectivity and electron energy-loss function. Calculations are performed using ab initio pseudopotential density functional method with the generalized gradient approximation. The cubic structure is optimized at zero pressure while the tetragonal structure is optimized under its structural phase transition pressure, which is previously calculated to be 6.0 GPa. Comparison between electronic and optical properties of the considered structures has been done. We find that the electronic and optical properties of the cubic phase are quite different from those of the tetragonal one.