LDA+U evaluation of the stability of low-index facets of LaCoO3 perovskite

We report ab initio calculations at the LDA+U level to examine the atomic configurations and stabilities of different terminations of the perovskite LaCoO3. Results of cleavage energies indicate that the propensity to reconstruct depends on the orientation of terminations. The stability of the reconstructed termination relates to the nominal charge of a given surface. O atoms on surfaces interact repulsively with each other. We discuss the thermodynamic stabilities of all terminations using the Grand potential. A stability diagram demonstrates that the ground termination is LaO-(001) p(1 × 1) surface in most cases, while it transforms to the LaO3-(111) p(1 × 1) surface in O-rich/La-poor condition. The results provide potential candidates for future studies of LaCoO3 surface catalysis.