Spectral function database for correlated materials using beyond-DFT methods

While DFT or DFT+U methods give quite accurate results for structural parameters in most materials, correct predictions of excited-state properties, even at a qualitative level, and other properties of correlated materials, usually require beyond-DFT methods. The existing materials databases, constructed in the spirit of the Materials Genome Initiative, are built almost exclusively by the DFT method and are thus very often making incorrect predictions for correlated materials. Various beyond DFT methods, such as meta-GGA, hybrid functionals, GW approximation, or dynamical mean-field theory have been developed to describe the electronic structure of correlated materials, but it is unclear how accurate these methods are when applied to a given strongly correlated solid. It is thus of pressing interest to compare their accuracy as applied to different categories of materials, and at the same time, to build the database of beyond-DFT calculations. We discuss a systematic study of these methods on a few training sets of correlated materials such as binary transition-metal oxides, Fe-pnictides & chalcogenides, and transition-metal dichalcogenides, and we compare theoretical predictions with experimental photoemission data, where available.