Consistent LDA'+DMFT approach to electronic structure of transition metal oxides: charge transfer insulators and correlated metals

摘要

We discuss the recently proposed LDA'+DMFT approach providing consistentparameter free treatment of the so called double counting problem arisingwithin the LDA+DMFT hybrid computational method for realistic stronglycorrelated materials. In this approach the local exchange-correlation portionof electron-electron interaction is excluded from self consistent LDAcalculations for strongly correlated electronic shells, e.g. d-states oftransition metal compounds. Then the corresponding double counting term inLDA+DMFT Hamiltonian is consistently set in the local Hartree (fully localizedlimit - FLL) form of the Hubbard model interaction term. We present the resultsof extensive LDA'+DMFT calculations of densities of states, spectral densitiesand optical conductivity for most typical representatives of two wide classesof strongly correlated systems in paramagnetic phase: charge transferinsulators (MnO, CoO and NiO) and strongly correlated metals (SrVO3 andSr2RuO4). It is shown that for NiO and CoO systems LDA'+DMFT qualitativelyimproves the conventional LDA+DMFT results with FLL type of double counting,where CoO and NiO were obtained to be metals. We also include in ourcalculations transition metal 4s-states located near the Fermi level missed inprevious LDA+DMFT studies of these monooxides. General agreement with opticaland X-ray experiments is obtained. For strongly correlated metalsLDA$^\prime$+DMFT results agree well with earlier LDA+DMFT calculations andexisting experiments. However, in general LDA'+DMFT results give betterquantitative agreement with experimental data for band gap sizes and oxygenstates positions, as compared to the conventional LDA+DMFT.