Phase Transitions in BiFeO₃ through Thermoelectric Parameters

The theoretical single crystal of BiFeO3 (BFO) with rhombohedral phase R3c was studied using Wu-Cohen (WC) and $\mathbf{W C}+\mathbf{U}$ exchange and correlation functionals. The representation of the core electrons was done through optimized Vanderbilt pseudopotentials (ONCV). The electronic band structure and density of states (DOS) were determined after the atoms of the system were relaxed. The results show a valence band densely populated compared to the conduction band, and whose band gap is close to 2.33 eV. Calculations of the thermoelectric parameters as a function of temperature are presented and indicate the existence of two-phase transitions in the range from 50 to 800 K, which are discussed.