Tackling nonlocal electronic correlations with the dynamical vertex approximation (A. Galler)

The dynamical mean-field theory (DMFT), in combination with density functional theory (DFT), has been developed into a powerful computational tool for materials with strong electronic correlations. Nevertheless, DMFT is based on the solution of a quantum impurity model and can account only for local electronic correlations. Diagrammatic extensions of DMFT such as the dynamical vertex approximation (DΓA) are attempting to include nonlocal correlations and long-range Coulomb interactions. In this talk, I will present my efforts to extend the DΓA methodology to ab-initio materials calculations (AbinitioDΓA). AbinitioDΓA represents a unifying framework which includes both, GW and DMFT-type of diagrams, but also important nonlocal correlations beyond, e.g. non-local spin fluctuations. I will first introduce the method and then present results for layered transition-metal oxides and the two-band Hubbard model.