"Striped" lanthanum cobaltite films: tracking oxygen vacancies formation, ordering, and transport through scanning electron microscopy and density functional theory*

Oxide-fuel solid cells are efficient at converting fuel to electricity and can function at very high temperatures. Since they rely on fast oxygen transport, it is crucial to understand the formation and transport of oxygen vacancies in candidate electrolytes. However, these properties are subtly dependent on the physics and electrochemistry of the target material. Oxygen-deficient lanthanum cobaltites are a family of perovskite-related materials known for their excellent oxygen transport.  We employ a combination of density functional theory and scanning transmission electron  microscopy  to examine the energetics and dynamics of oxygen vacancy ordering in the (1 1 1) oriented LaCoO_3-δ on SrTiO₃. Specifically, we track the formation, spontaneous ordering, and transport of oxygen vacancies, and conclude on the effects of high index interfaces on oxygen transport properties.