Interface layer chemistry dependent oxygen defect formation in BaZrO3(110)/SrTiO3(100) heterostructures”.

Abstract

Mismatched complex oxide thin films and heterostructures based on perovskites have key applications in technologies such as solid oxide fuel cells, batteries, and solar cells because of emerging properties at the interface. Although lattice mismatch and resulting misfit dislocations are one of the fundamental reasons for the emergence of new properties at the interface, their precise role is not well understood. In light of this, we have used first principles calculations to study BaZrO3(110)/SrTiO3(100) heterostructures for thin film electrolyte applications and predict the interfacial stability as a function of termination layer chemistry. Atomic scale structure and electronic structure of oxygen vacancies at doped interfaces was further studied to comprehend their stability and location preference at the interface. Strong dependence of oxygen vacancy formation on termination layer chemistry is observed. Among the four possible interfaces, oxygen vacancies exhibit a thermodynamic preference to form at the TiO2–ZrO2 interface. Results herein shed light on the fundamental aspects of mismatched perovskite oxide interfaces and their influence on thermodynamic stability of oxygen vacancy defects, which influences ionic transport and is imperative to design next-generation thin film oxide electrolytes.