First-principles Study of Antisite Defects in Orthorhombic PbZrO3

First-principles calculations based on density functional theory (DFT) within local density approximation were employed to investigate the antisite defects, including Pb-Zr and Zr-Pb, in orthorhombic PbZrO3 by determining their defect formation energies. The formation energies of antisite defects were then compared with those of other dominant defects, i.e., lead Pb, zirconium Zr, and oxygen O vacancies to examine the likelihood of their existence. Our results revealed that Pb-Zr defect in neutral charge state is the most dominant defect under O-rich or oxidizing condition in agreement with the previous work. In addition, there is a little structural relaxation when the Zr atom is replaced by Pb atom to form Pb-Zr defect in neutral charge state. In opposite, under O-poor or reducing condition, the formation energies of antisite defects are quite high and higher than those of vacancy defects. This suggests that antisite defects are unlikely to form under reducing condition.