2DEGs at Perovskite Interfaces between KTaO(3) or KNbO(3) and Stannates

We report density functional studies of electron rich interfaces between KTaO(3) or KNbO(3) and CaSnO(3) or ZnSnO(3) and in particular the nature of the interfacial electron gasses that can be formed. We find that depending on the details these may occur on either the transition metal or stannate sides of the interface and in the later case can be shifted away from the interface by ferroelectricity. We also present calculations for bulk KNbO(3), KTaO(3), CaSnO(3), BaSnO(3) and ZnSnO(3), showing the different transport and optical properties that may be expected on the two sides of such interfaces. The results suggest that these interfaces may display a wide range of behaviors depending on conditions, and in particular the interplay with ferroelectricity suggests that electrical control of these properties may be possible.