Competing strain effects in reactivity of LaCoO3 with oxygen

Planar strain effects on oxygen-vacancy formation and oxygen adsorption on LaCoO3 are shown to manifest through competing mechanisms. Through first-principles calculations, we demonstrate that these unit processes are facilitated by elastic stretching. On the other hand, spin-state transitions and Co-O bond exchange hinder these processes by trapping the lattice oxygen with increasing tensile strain. A transition from chemisorption to physisorption of the oxygen molecule is identified at high strains. Insights on charge-density profiles, density of electronic states, and stress thresholds suggest the possibility of tuning strain-mediated reactivity in LaCoO3 and related perovskite oxides.