High-mobility two-dimensional electron gas in SrGeO3- and BaSnO3-based perovskite oxide heterostructures: an ab initio study

Abstract

We explored the possibility of producing a high-mobility two-dimensional electron gas (2DEG) in the LaAlO₃/SrGeO₃ and LaGaO₃/BaSnO₃ heterostructures using first-principles electronic structure calculations. Our results show that the 2DEG occurs at n-type LaAlO₃/SrGeO₃ and LaGaO₃/BaSnO₃ interfaces. Compared to the prototype LaAlO₃/SrTiO₃, LaAlO₃/SrGeO₃ and LaGaO₃/BaSnO₃ systems yield comparable total interfacial charge carrier density but much lower electron effective mass (nearly half the value of LaAlO₃/SrTiO₃), thus resulting in about twice larger electron mobility and enhanced interfacial conductivity. This work demonstrates that SrGeO₃ and BaSnO₃ can be potential substrate materials to achieve a high-mobility 2DEG in the perovskite-oxide heterostructures.