High-Throughput Prediction of Thermodynamic Stabilities of Dopant-Defect Clusters at Misfit Dislocations in Perovskite Oxide Heterostructures

Complex oxide heterostructures and thin films have emerged as promising candidates for diverse applications, wherein interfaces formed by joining two different oxides play a central role in novel properties that are not present in the individual components. Lattice mismatch between the two oxides leads to the formation of misfit dislocations, which often influence vital material properties. In oxides, doping is used as a strategy to improve properties, wherein inclusion of aliovalent dopants leads to formation of oxygen vacancy defects. At low temperatures, these dopants and defects often form stable clusters. In semicoherent perovskite oxide heterostructures, the stability of such clusters at misfit dislocations, while not well understood, is anticipated to impact interface-governed properties. Herein, we report atomistic simulations elucidating the influence of misfit dislocations on the stability of dopant-defect clusters in SrTiO3/BaZrO3 heterostructures. SrO–BaO, SrO–ZrO2, BaO–TiO2, and ZrO2–TiO2 interfaces having dissimilar misfit dislocation structures were considered. High-throughput computing was implemented to predict the thermodynamic stabilities of 275,610 dopant-defect clusters in the vicinity of misfit dislocations. The misfit dislocation structure of the given interface and corresponding atomic layer chemistry play a fundamental role in influencing the thermodynamic stability of geometrically diverse clusters. A stark difference in cluster stability is observed at misfit dislocation lines and intersections as compared to the coherent terraces. These results offer an atomic scale perspective of the complex interplay between dopants, point defects, and extended defects, which is necessary to comprehend the functionalities of the perovskite oxide heterostructures.