Competing strain effects in reactivity of LaCoO[subscript 3] with oxygen

Planar strain effects on oxygen-vacancy formation and oxygen adsorption on LaCoO[subscript 3] 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 LaCoO[subscript 3] and related perovskite oxides.United States. Dept. of Energy. Office of Basic Energy Sciences (Grant no. DE-SC0002633)TeraGrid (Grant no. TG-ASC090058