High Mobility Two-Dimensional Electron Gas at the BaSnO3/SrNbO3 Interface.

Oxide two-dimensional electron gases (2DEGs) promise high charge carrier concentrations and low-loss electronic transport in semiconductors such as BaSnO3 (BSO). ACBN0 computations for BSO/SrNbO3 (SNO) interfaces show Nb-4d electron injection into extended Sn-5s electronic states. The conduction band minimum consists of Sn-5s 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 ∼1021 cm-3. Experimental studies of analogous BSO/SNO interfaces grown by molecular beam epitaxy confirm significant charge transfer from SNO to BSO. In situ angle-resolved X-ray photoelectron spectroscopy studies show an electron density of ∼4 × 1021 cm-3. The consistency of theory and experiments show that BSO/SNO interfaces provide a novel materials platform for low loss electron transport in 2DEGs.