Oxygen vacancy segregation in grain boundaries of BaZrO3 using interatomic potentials

We have used classical interatomic potentials to determine the structure, interface energy and oxygen vacancy segregation energies of eight different grain boundaries (GBs) in BaZrO3 with tilt axis [1¯10]. Two of these have been studied previously with density functional theory and the agreement is satisfactory. The results suggest that oxygen vacancies prefer to reside near the boundary interface for all these GBs. The minimum segregation energies range between − 1.86 eV and − 0.57 eV, and the typical core width is about 10 Å. The resulting depletion layers have been evaluated using a thermodynamic space-charge model. Space-charge potential barriers between 0.2 and 0.8 eV were obtained with dopant concentrations of 5% and 10%.

► We model 8 different tilt grain boundaries in BaZrO3 with interatomic potentials.
► Agreement with density functional theory is satisfactory.
► All grain boundaries favor oxygen vacancy segregation to the core region.
► We apply a space-charge model to the obtained segregation energies.
► Space-charge potentials between 0.2 and 0.8 eV are obtained.