First principles study of Pb vacancies in PbTiO3

Electronic and ionic structures of lead vacancies in PbTiO3 were studied using an ab initio approach. Even though the lead vacancy is found to be an acceptor with stable charge states ranging from 2- to 4- it does not form a tightly bound defect pair with a double donor oxygen vacancy. The formation of distant and nearby lead-vacancy–oxygen-vacancy pairs is shown to be exothermic under certain growth conditions.