Tailoring interfacial properties in CaVO3 thin films and heterostructures with SrTiO3 and LaAlO3: A DFT +DMFT study
In this paper we use density functional theory combined with dynamical mean-field theory (DFT +DMFT ) to study interface effects between the correlated metal Ca V O3 and the two typical substrate materials Sr Ti O3 and La Al O3 . We find that the Ca V O3/Sr Ti O3 interface has only a marginal influence on the Ca V O3 thin film, with the dominant effect being the (bulklike) epitaxial strain imposed by the large lattice mismatch, rendering the Ca V O3 film insulating due to the enhanced orbital polarization related to the strong level splitting between the t2 g orbitals. In contrast, at the polar Ca V O3/La Al O3 interface, the presence of the interface can have a huge effect on the physical properties, depending both on the specific interface termination and on the specific boundary conditions imposed by the multilayer geometry. We compare three approaches to modeling the Ca V O3/La Al O3 interface, all of which impose a different set of (electrostatic) boundary conditions. Our results demonstrate that different substrates, interface terminations, and electrostatic boundary conditions can drastically affect the properties of thin-film heterostructures, indicating the potential tunability of the interfacial properties via multilayer engineering.