Electronic structure of BiFeO3 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 ${\mathrm{BiFeO}}₃$, a multiferroic material with an electron band gap larger than its bare bandwidth. Within the ${\mathrm{Fe}}³⁺$ 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 ${\mathrm{BiFeO}}₃$, predicting broad orbital- and spin-polarized features at low temperatures. Our proposal for ferromagnetic ${\mathrm{BiFeO}}₃$ 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.