Exploring the role of nonlocal Coulomb interactions in perovskite transition metal oxides

TL;DR

This study uses advanced DFT methods to analyze how nonlocal Coulomb interactions influence the electronic and magnetic properties of perovskite transition metal oxides, revealing the importance of inter-site interactions.

Contribution

It introduces a comprehensive DFT+U+V approach with parameters derived from constrained RPA, highlighting the significance of nonlocal interactions in these materials.

Findings

Nonlocal Coulomb interactions are comparable to local ones.

Inter-site V is crucial for reproducing experimental magnetic orders.

Hybridization effects increase with d-orbital occupation.

Abstract

Employing the density functional theory incorporating on-site and inter-site Coulomb interactions (DFT+U+V), we have investigated the role of the nonlocal interactions on the electronic structures of the transition metal oxide perovskites. Using constrained random phase approximation calculations, we derived screened Coulomb interaction parameters and revealed a competition between localization and screening effects, which results in nonmonotonic behavior with d-orbital occupation. We highlight the significant role and nonlocality of inter-site Coulomb interactions, V, comparable in magnitude to the local interaction, U. Our DFT+U+V results exemplarily show the representative band renormalization, and deviations from ideal extended Hubbard models due to increased hybridization between transition metal d and oxygen p orbitals as occupation increases. We further demonstrate that the inclusion of the inter-site V is essential for accurately reproducing the experimental magnetic order in transition metal oxides.