Investigating conduction band stability in SrTiO3

Abstract

We present a comprehensive investigation of the electronic structure of SrTiO3 through experimental x-ray emission spectroscopy, x-ray absorption spectroscopy (XAS), and density functional theory calculations. Our results reveal that the electronic states near the band edges predominantly arise from hybridization between O 2p, Sr 4d, and Ti 3d orbitals. Comparison with binary constituents SrO and TiO2 shows that SrTiO3 exhibits intermediate electronic properties: many spectral features resemble those of the binary oxides, although distinct differences indicate that a simple additive description is only approximate. Core hole effects are minimal, with negligible exciting features presented in O K XAS, indicating efficient charge screening. Furthermore, our analysis of oxygen-deficient SrTiO3−x revealed robust electronic structures and high optical transparency, even with vacancy-induced shallow donor states and enhanced carrier concentrations. These findings highlight the resilience and defect-tolerance of SrTiO3, underscoring its promise for energy applications and oxide electronics.