Interplay of charge-transfer and Mott-Hubbard physics approached by an efficient combination of self-interaction correction and dynamical mean-field theory
Late-transition-metal oxides with small charge-transfer energy D raise issues for state-of-the-art correlated electronic structure schemes, such as the combination of density functional theory (DFT) with dynamical mean-field theory (DMFT). The accentuated role of the oxygen valence orbitals in these compounds asks for an enhanced description of ligand-based correlations. Utilizing the rocksaltlike NiO as an example, we present an advancement of charge self-consistent DFT + DMFT by including self-interaction correction (SIC) applied to oxygen. This introduces explicit on-site O correlations as well as an improved treatment of intersite p−d correlations. Due to the efficient SIC incorporation in a pseudopotential form, the DFT + sicDMFT framework is an advanced but still versatile method to address the interplay of charge-transfer and Mott-Hubbard physics. We revisit the spectral features of stoichiometric NiO and reveal the qualitative sufficiency of local DMFT self-energies in describing spectral peak structures usually associated with explicit nonlocal processes. For LixNi1−xO, prominent in-gap states are verified by the present theoretical paper.