Self-consistent DFT+U+V study of ground state properties in BiFeO3 system

Abstract

The Hubbard-corrected Density Functional Theory (DFT+U and DFT+U+V) was employed within the generalized gradient approximation (GGA) framework, utilizing both Projector Augmented Wave (PAW) and Norm-Conserving (ONCV) pseudopotentials, to investigate the ground state properties of the strongly correlated insulator system BiFeO₃ (BFO). The on-site U correction was used to describe the localized nature of the Fe(3d) manifolds since each FeO₆ octahedron of the BFO structure exhibits strong correlations and structural distortions in the Fe-O bonds. The inter-site V correction was used to reproduce the strong hybridization between neighboring Fe(3d) and O(2p) manifolds. The U and V parameters were calculated using linear-response theory within the Orthogonalized Atomic Orbitals (OAO) Hubbard projectors as implemented in the Quantum ESPRESSO (QE) suite. The derived values for the on-site and inter-site Hubbard parameters were used to study the structural, electronic, and magnetic properties of our system. The obtained results are compared with previous theoretical and experimental studies, showing the usefulness of considering inter-site interactions to adequately describe the ground state properties of a strongly correlated system.