A DFT+DMFT perspective on correlated oxide interfaces

Complex transition metal oxides have become a platform for materials design and discovery because they are host to a manifold of interesting physical phenomena and have a wide range of control parameters. However, the emerging phenomena at interfaces and multilayers of such materials pose a particular challenge, both theoretically and experimentally, due to the complexity of coupling different degrees of freedom at the interface.

In this talk, I will describe our recent theoretical efforts in exploring interface phenomena in strongly interacting systems using a combination of density functional theory (DFT) and dynamical mean-field theory (DMFT). I will review electronic and structural interface reconstruction mechanisms connected to thin film geometries, substrate and interface effects in light of electronic structure modelling.

One example is the Hund’s metal Sr₂RuO₄, for which it has been shown that the application of uniaxial compressive strain induces a Lifshitz transition of the Fermi surface due to a van Hove singularity in the vicinity of the Fermi level. I will report on our advances to study the strain-induced changes in the Fermi surface topology, employing the recently developed Fork Tensor-Product States impurity solver[1], which allows for a full treatment of spin-orbit coupling within DMFT. As a second example I will address multilayers composed of the Mott insulator LaVO₃ and the correlated metal SrVO₃, which acts as a layerwise dopant.

I will discuss the length scales of structural and electronic couplings and address recent advances in tackling numerical challenges associated with the DMFT embedding.

[1] D. Bauernfeind et al., Phys. Rev. X 7, 031013 (2017)