Oxygen vacancy segregation in grain boundaries of BaZrO3 using interatomic potentials

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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 −1.86eV and −0.57eV, and the typical core width is about 10Å. The resulting depletion layers have been evaluated using a thermodynamic space-charge model. Space-charge potential barriers between 0.2 and 0.8eV were obtained with dopant concentrations of 5% and 10%.