Electronic Structure of BiFeO3 in Different Crystal Phases

The electronic structure of different phases of BiFeO3 were calculated by using density functional theory. The DFT+U and semilocal Tran Blaha modified Becke Johnson potential were used. DFT+U results are in good agreement with previous calculations. Our results have shown that in case of R3c, Pnma, Pn2(1)a BiFeO3 has G-ntiferromagnetic ordering and C-antiferromagnetic in case of Cm space group. In all calculated structures BiFeO3 is a semiconductor with the band gap: 2.26 eV (2.27 eV) for R3c, 1.91 eV (1.66 eV) for Pnma, 1.99 eV (2.18 eV) for Pn2(1)a and 2.09 eV (2.55 eV) for Cm within DFT+U (Tran Blaha modified Becke Johnson).