Importance of ligand on-site interactions for the description of Mott-insulators in DFT+DMFT

Abstract Calculations combining density functional theory (DFT) and dynamical mean-field theory (DMFT) for transition metal (TM) oxides and similar compounds usually focus on improving the description of the TM d states. Here, we emphasize the importance of also accounting for corrections of the ligand p states. We demonstrate that focusing exclusively on improving the description of the TM d states results in difficulties to obtain the correct insulating behavior for a variety of materials, and requires to use values for the local interaction parameters that are inconsistent with values obtained using, e.g ., the constrained random phase approximation (cRPA). We demonstrate that, to a large part, these inconsistencies arise from using local/semi-local DFT as starting point for computing interaction parameters, and we show that applying a simple empirical correction to the low energy states not included in the correlated subspace results in improved values for the interaction parameters that then allow to obtain the correct insulating behavior. Moreover, we show that applying an approximate but realistic Hartree-Fock-like correction specifically to the O p orbitals, when they are explicitly included in the DMFT subspace, significantly improves the quantitative accuracy of the DFT+DMFT description for prototypical Mott insulators, including LaTiO 3 , LaVO 3 , and the perovskite rare-earth nickelates (RNiO 3 ).