Investigation of Optical Property of Tetragonal BiFeO3

  ing the full potential linearized augmented plan wave in framework density functional theory(DFT) with wien2k code. The band structure and energy gap of the bulk structures are calculated with GGA-PBE, GGA+U and GGA+MBJ approximations, and results obtained from the MBJ function are more consistent with the reported experimental results. The optical properties such as real and imaginary parts of dielectric function, absorption coefficient, reflection coefficient, refractive index, extinction coefficient, conductivity and electron energy loss spectrum have been calculated and studied. The results show that the bulk of tetragonal ferrite bismuth is a semiconductor with a optical gap of 2.7 electron volt. Since compound has magnetic properties, all calculations of compound is performed in full spin polarization.