Internal consistency of multi-tier GW+EDMFT

While the approach is free from ad-hoc parameters, it requires a selection of appropriate energy windows for describing low-energy and strongly correlated physics. In this study, we test the consistency of the multi-tier description by considering different low-energy windows for a series of cubic SrXO₃ (X = V, Cr, Mn) perovskites.

Specifically, we compare the 3-orbital t 2g model, the 5-orbital t 2g + e g model, the 12-orbital t 2g + O p model, and (in the case of SrVO₃) the 14-orbital t 2g + e g + O p model and compare the results to available photoemission and X-ray absorption measurements. The multi-tier method yields consistent results for the t 2g and t 2g + e g low-energy windows, while the models with O p states produce stronger correlation effects and mostly agree well with experiment, especially in the unoccupied part of the spectrum.