Spatial charge distribution and conductivities of the LaAlO3/SrTiO3 interfaces: A theoretical study

The electronic properties of the charge carriers at the LaAlO3/SrTiO3 interfaces are investigated by first principles studies. For the n-type interface, the carriers are located only on the SrTiO3 side. For the p-type interface, the carriers are highly localized at the interface. A critical thickness of the LaAlO3 overlayer exists, below which, the interface is insulating. Moreover, we show that the effective masses and mobilities of the carriers are spatially anisotropic and have a strong disparity for the two types of carriers. These results are consistent with experimental observations and are explained by the band structures and alignments of the consisting oxides and their interaction at the interfaces.