Effects of charge self-consistency in DFT+DMFT calculations for complex transition metal oxides

During recent years, the combination of density functional theory (DFT) and dynamical mean-field theory (DMFT) has become a widespread tool to calculate properties in correlated materials. The basic idea of the method is that the electronic degrees of freedom can be separated into a weakly interacting part, for which a standard DFT treatment is adequate, and a correlated subspace, which requires a more elaborate treatment of the electron-electron interaction. The latter leads, in general, to a redistribution of electrons within the correlated subspace compared to the DFT result. This change should then enter, in a self-consistent way, the effective potential felt by the weakly interacting electrons, which is achieved by iterating between DFT and DMFT steps. However, such a charge self-consistent (CSC) DFT+DMFT calculation leads to a higher computational cost compared to simpler one-shot calculations, where this charge rearrangement is neglected. Here, we examine the effect of CSC in DFT+DMFT calculations compared to simpler one-shot calculations for two instructive example materials, CaVO₃ and LuNiO_3, to clarify in which cases the more complex CSC treatment is necessary and in which cases the simpler one-shot calculation is sufficient.