Influence of misfit dislocations on oxygen vacancy migration at SrTiO₃/BaZrO₃ heterointerfaces

Mismatched complex oxide heterostructures and thin films have remarkable promise for next-generation electrolytes in solid oxide fuel cells (SOFCs), wherein misfit dislocations impact interfacial ionic transport. Nevertheless, fundamental understanding of atomic scale structure of misfit dislocations and their influence on oxygen vacancy migration at functional interfaces is lacking. For SrTiO₃/BaZrO₃ heterostructure, we employed atomistic simulations to predict the thermodynamic stability and atomic scale structure of misfit dislocations, which is found to depend on interface layer chemistry. Using high-throughput simulations, thousands of activation energy barriers were determined for oxygen vacancy migration at different interfaces. Higher activation energies are observed in the vicinity of dopants, whereas migration paths near misfit dislocation lines are lower in energy, but vary somewhat depending on interface chemistry. This data is currently being utilized to develop a kinetic lattice Monte Carlo model for tracing oxygen vacancy diffusion at oxide interfaces. Results on oxygen ion migration at oxide heterointerfaces offer new opportunities to unravel the untapped potential of thin film SOFC electrolytes.