Metal-insulator transition and charge transfer in complex oxide heterostructures from DFT+DMFT

We study the interplay between several control mechanisms on the emerging functionalities of complex oxide thin films and heterostructures composed of different early transition metal oxides, including correlated metals, Mott insulators and band insulators, using a combination of density functional theory (DFT) and dynamical mean-field theory (DMFT).
We discuss several examples where factors, such as e.g. lattice missmatch-induced epitaxial strain, dimensional confinement, and multilayer engineering lead to modifications of structural as well as electronic properties, that give rise to a variety of phases not present in the corresponding bulk compounds.
In particular, we address multilayers composed of materials that share the same B-site atom, such as, for example, LaVO3/SrVO3 and LaTiO3/CaTiO3, where the electronegativity difference leads to charge transfer from the higher valent to the lower valent transition metal cation, rendering the interface to be more metallic than the bulk constituents on a length scale of few unit cells in good agreement with experimental results. We draw a conceptual comparison to other types of heterostructures and give an overview on interface effects in early transition metal oxides.