Investigation of the spectral properties and magnetism of BiFeO3 by dynamical mean-field theory

Electronic structure of BiFeO3 in the presence of strong electronic correlations

“…Bulk BiFeO 3 is known to be a wide band gap Mott insulator above T N [13,14]. The gap value obtained from correlated [generalized gradient approximation plus dynamical meanfield theory (GGA+DMFT)] band structure calculations for the rhombohedral R3c structural phase was found to be close to 1.2 eV [13].…”

“…Due to the large orbital radius of the Bi-6s 2 lone pairs, the crystal structure of Bi perovskites is usually distorted to low symmetries, producing spontaneous ferroelectric polarization along certain crystallographic directions [6]. Among the Bi perovskites, BiFeO 3 is the most systematically studied system both from theory [7][8][9][10][11][12][13][14] and experimental [3,4,[15][16][17][18][19][20][21][22][23][24] perspectives.…”

“…Theoretically, magnetically induced electronic reconstruction in BiFeO 3 has been investigated using firstprinciples density functional theories (DFT) [4,8,10,23]. Particularly relevant in this context is the recent density functional dymanical mean-field theory (DFDMFT) study by S. Paul et al [14] (see our discussion below), where the spectral properties of paramagnetic and antiferromagnetic phases of BiFeO 3 were investigated and compared to photoemission spectra. However, to the best of our knowledge, there have been no previous DFDMFT investigations on the interplay between dynamical multiorbital (MO) interactions, oxidation state, and ferromagnetism, all inducing electronic orbital reconstruction in BiFeO 3 .…”

“…Recently, Paul et al [14] have used the LDA+DMFT approach to compute the valence-band photoelectron and magnetic excitation spectra of BiFeO 3 . The results of this study were shown to be in good agreement with the experimental data [22] for the occupied states, whereas the LDA+U method fails to capture the general features of the measured spectra.…”

“…Likewise, here we present a self-consistent study of electronic structure calculations using the LDA+DMFT approach for BiFeO 3 parent compound. The calculated density-of-states (DOS) is compared with experimental photoemission (PES) [14,22] and inverse photoemission spectroscopy (IPES) [24] data. We show how this can provide a consistent explanation for the more relevant electron correlation fingerprints in the occupied and unoccupied states as well as to optical-absorption spectra of BiFeO 3 singlecrystal [21] within the same theoretical framework.…”