Electronic Reconstructions in the Transition Metal–Free Heterostructures: LaAlO₃/SrGeO₃

Based on density functional theory, we have investigated the electronic reconstruction in the polar LaAlO₃ slabs and LaAlO₃/SrGeO₃ (LAO/SGO) heterostructures. Non-transition-metal component SGO could be used to create LAO/SGO heterostructures with little lattice mismatch. In these heterostructures, polar LAO truncated by the non-polar SGO would induce electronic reconstruction. Residual potentials in film normal direction are found because of the incompleteness of the reconstruction, since there are band gaps in LAO and SGO bulk. Such residual potentials are very close to unsupported LAO slabs and influenced by the interspacing of the interfaces. The thickness of the two-dimensional electron gas in the LAO/SGO heterostructures has been also estimated, which is believed much wider distributed than the corresponding holes and the unsupported slabs.