Ab Initio Studies on the Structural and Electronic Properties of Bismuth Ferrite Based on Ferroelectric Hexagonal Phase and Paraelectric Orthorhombic Phase

Abstract

The structural and electronic properties of bismuth ferrite (BFO) in ferroelectric hexagonal phase and paraelectric orthorhombic phase are investigated using ab initio density functional theory calculation. Calculations based on generalized gradient approximation GGA–PBEsol functional with semi-empirical Hubbard U method show good results for the structural and electronic localization of Fe 3d electrons and are consistent with experimental data. In addition, the calculated electronic band structure of BFO in paraelectric orthorhombic phase shows a smaller energy band gap than BFO in ferroelectric hexagonal phase. Thus, this calculation is consistent with the experimental data. The function of the stereochemically active lone pair of Bi 6s² and chemical bonding of Fe‒O and Bi‒O on the structural instability of BFO are further elucidated in this study.

Keywords:

• Bismuth ferrite
• ferroelectric/paraelectric phase
• density functional theory (DFT)

Acknowledgments

The authors would like to acknowledge the Institute of Science (IOS), Universiti Teknologi MARA (UiTM), Malaysia for the facilities and financial support provided (RAGs). MK Yaakob also wishes to acknowledge UiTM and the Ministry of Education (MOE), Malaysia for the scholarship awarded.