Based on DFT Calculations, Some Physical Properties of The Perovskite Compound (SrTiO3) were Calculated

This study systematically investigates the structural, electronic, and optical properties of cubic perovskite SrTiO3 using Density Functional Theory (DFT) with Local Density Approximation (LDA), Generalized Gradient Approximation (GGA), and meta-GGA (M-GGA) functionals, and compares the results with experimental data. Structural optimization reveals lattice parameters of 3.848 Å (LDA), 3.943Å (GGA), and 3.907 Å (M-GGA), showing LDA’s underestimation and GGA’s slight overestimation relative to the experimental value (3.905 Å). M-GGA provides the closest agreement, reflecting its improved treatment of exchange-correlation effects. Electronic structure calculations highlight band gap trends: LDA (1.987eV) and GGA (2.128 eV) significantly underestimate the direct G→G gap, while M-GGA (2.218eV) partially mitigates this error, though still below the experimental 3.2 eV. Across functionals, the conduction band minimum (Ti 3d) and valence band maximum (O 2p) are constant, with very small contributions from Sr. Strong Ti-O hybridization near the Fermi level and t2g-eg splitting of Ti 3d states are confirmed by density of states (DOS) analysis, with M-GGA showing different features. Optical properties (dielectric function, absorption coefficient) computed via LDA/GGA exhibit redshifted absorption edges due to band gap underestimation, while M-GGA aligns better with experimental UV onset (~3.2 eV). All functionals capture dominant optical. Also calculated each Mulliken charge distribution, bond Length, and population analysis using the same approximation mentioned above.