Layered–Control Approach to Tune The Mobility of Perovskite SrTiO₃: A Density Functional Theory Prospects

Abstract

The advancement of epitaxial technology has enabled the simulation of oxide heterostructures (HS) with unique interfacial material characteristics not found in bulk materials. Recent discoveries of emergent phenomena of definite oxide interfaces have attracted much attention on oxide HS. This work explored the possibility of tuning the electron mobility of SrTiO3 (STO) through CaSnO3/SrTiO3 and ZnSnO3/SrTiO3 HSs, based on density functional theory (DFT). Based on the Sn–5s states of CSO and ZSO with more substantial band dispersion than Ti–3d states of STO, near conduction band minimum (CBM), our simulated results suggest that the bandgaps of CSO/STO (0.502 eV) and ZSO/STO (0.349 eV) HS systems are much smaller than bulk STO (1.802 eV). The effective electron masses also show much smaller values (0.31 and 0.40 m0) and (0.38 and 0.52 m0) for (CSO)7/(STO)4 and (ZSO)1/(STO)4 for HS systems compared to bulk STO (7.03 and 0.94 m0) along Γ–X and Γ–M direction. The bandgap and effective electron masses results suggest that the bandgap of STO can be well controlled and tuned by the thin film layer numbers of CSO and ZSO with better electron transportability.