B 99 , 045112 ( 2019 ) Electronic structure of BiFeO 3 in the presence of strong electronic correlations

Using density-functional dynamical mean-field theory (DFDMFT) we show the importance of multiorbital electronic correlations in determining the insulating state of BiFeO3, a multiferroic material with an electron band gap larger than its bare bandwidth. Within the Fe3+ oxidation state and using realistic values for the on-site Coulomb interaction, we unveil strongly correlated key features probed in x-ray photoelectron and absorption spectra, showing good qualitative theory-experiment agreement. We explore the electronic reconstruction hidden in ferromagnetic BiFeO3, predicting broad orbitaland spin-polarized features at low temperatures. Our proposal for ferromagnetic BiFeO3 is expected to be an important step to understanding the emergent correlated electronic structure of magnetoelectronic and spintronic materials with persisting ordered localized moments coexisting with Coulomb reconstructed electronic states.