The polarization of a nearest-neighbor (nn) Pb-O vacancy pair in PbTiO3 is calculated, using the modern theory of polarization, implemented in the density functional theory ultrasoft pseudopotential formalism. The dipole moment per divacancy is about 2.228 e rnn, where rnn is the vector from the VPb site to the VO site. The value is slightly larger than the value of 2 e rnn for a purely ionic model of PbTiO3. The dipole moment is about twice as large as typical polarizations per cell in Pb-based ferroelectrics, which indicates that VPb compensated by Vo can be an important source of local polarization and electri fields in Pb-containing pervoskites.
Physical Review B (Condensed Matter and Materials Physics)
and Burton, B.
Dipole Moment of a Pb-O Vacancy Pair in PbTiO<sub>3</sub>, Physical Review B (Condensed Matter and Materials Physics), [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=850779
(Accessed December 6, 2023)