First principle study of band gap nature, spontaneous polarization, hyperfine field and electric field gradient of desirable multiferroic bismuth ferrite (BiFeO3)

Abstract

Electronic band structure, spontaneous polarization, hyperfine fields and electric field gradients (EFG) of the desirable multiferroic BiFeO3 (BFO) are explored in R3c space group, using density functional theory. Improved TB-mBJ approach resolves the long-standing inconsistency between the theoretical and experimental band gap nature and value of BFO. In this study the calculated direct band gap is 2.84 eV, which was reported indirect band structures in other theoretical studies. The ferroelectric spontaneous polarization 88 μC/cm2 by PBE-GGA and 81 μC/cm2 by TB-mBJ were obtained using the Berry phase approach. Furthermore, the hyperfine interaction and EFG of the compound are also investigated.