Metal-insulator transitions 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 in early transition metal oxides using a combination of density functional theory (DFT) and dynamical mean-field theory (DMFT).
We discuss factors, such as e.g. lattice missmatch-induced epitaxial strain, dimensional confinement, and substrate effects, which can lead to modifications of structural as well as electronic properties. This can result in a metal-insulator transition in the correlated metal CaVO3, where we address the effect of a substrate in the simulation and draw a conceptual comparison between the two typical substrate materials, SrTiO3 and LaAlO3, and how they affect the CaVO3 thin film properties. We demonstrate that in the first case the influence of the interface is marginal beyond the effect of epitaxial strain, such that the substrate need not necessarily be included in the simulations. For LaAlO3, on the other hand, we show that different choices of the simulation cell can lead to strong modifications of the materials properties as a result of the associated electrostatic boundary conditions. We demonstrate how this can give rise to an enlarged spectrum of thin film properties via multilayer engineering.