Electronic structure, band offset, and interface electron population of the LaInO₃/BaSnO₃ system

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Perovskite oxides and their heterostructures exhibit a wide range of functional properties. Among these materials, BaSnO₃/LaInO₃ heterostructures form high-mobility two-dimensional electron gases (2DEGs) at their interfaces. In particular, room-temperature electron mobilities exceeding 100 cm²/Vs were enabled by recent advances in thin-film growth. This work presents a combined experimental and theoretical study of the electronic structure of BaSnO₃, LaInO₃, and BaSnO₃/LaInO₃ heterostructures with varying LaInO₃ overlayer thicknesses. Soft and hard X-ray photoelectron spectroscopy (SXPS and HAXPES) measurements are combined with densities of states (DOS) derived from hybrid density functional theory (DFT) calculations. The analysis of core, semi-core, and valence states allows to arrive at a comprehensive understanding of the chemical bonding and electronic structure in the parent oxides as well as the formed heterostructures. For the BaSnO₃/LaInO₃ heterostructure, the band offset and population of 2DEG states at the interface is directly probed using HAXPES.