Strain effects on the structural, electronic, optical, and thermoelectric properties of SrTiO3

This study investigates the effect of triaxial strain on the structural, electronic, optical, and thermoelectric properties of the perovskite oxide SrTiO₃ using first-principles calculations based on Density Functional Theory (DFT) within the Generalized Gradient Approximation (GGA), as implemented in the WIEN2k code. Compressive and tensile strains were systematically applied to explore their impact on the material's behavior. The results show that the crystal structure retains its cubic symmetry under all strain conditions. The electronic bandgap is found to decrease under tensile strain and increase under compressive strain, with values ranging from 1.99 eV to 3.41 eV. Optical analysis reveals that tensile strain enhances both light absorption and optical conductivity in the visible and ultraviolet regions. Thermoelectric properties were evaluated using the BoltzTraP code, highlighting the evolution of the Seebeck coefficient, power factor, and electrical and thermal conductivities at 300 K and 800 K. These findings provide insights into strain engineering of SrTiO₃ for advanced optoelectronic and thermoelectric applications.