Dielectric-permittivity-driven charge carrier modulation at oxide interfaces

High-quality bilayers of La-doped SrTiO(3) (STO) and LaAlO(3) (LAO) on SrTiO(3) have been grown controlling the location and behavior of the charge carriers by changing the thicknesses of the layers, which are dielectrically mismatched. In this system, the charge carriers are created at the La: SrTiO(3)/LAO interface and spread out toward the substrate due to the increase in dielectric constant as the temperature is lowered. When the electrons reach the interface of the La: SrTiO(3) and the pure STO, they display enhanced mobility in the quantum well at that interface for specific thicknesses.