Oxide two-dimensional electron gases (2DEGs) promise high charge carrier concentrations and low-loss electronic transport in semiconductors such as BaSnO$_{ 3}$ (BSO). ACBN0 computations for BSO/SrNbO$_{ 3}$ (SNO) interfaces show Nb-4$\textit{ d}$ electron injection into extended Sn-5$\textit{ s}$ electronic states. The conduction band minimum consists of Sn-5$\textit{ s}$ states ~1.2 eV below the Fermi level for intermediate thickness 6-unit cell BSO/6-unit cell SNO superlattices, corresponding to an electron density in BSO of ~10$^{ 21}$ cm$^{ -3}$. Experimental studies of analogous SNO/BSO interfaces grown by molecular beam epitaxy confirm significant charge transfer from SNO to BSO. $\textit { In situ}$ angle-resolved X-ray photoelectron spectroscopy studies show an electron density of ~4 $\times$ 10$^{ 21}$ cm$^{ -3}$. The consistency of theory and experiment shows that BSO/SNO interfaces provide a novel materials platform for low loss electron transport in 2DEGs.
Categories: cond-mat.mtrl-sci