Stabilization mechanisms of LaFeO₃ (010) surfaces determined with first principles calculations

Density functional theory is used to determine the stabilization mechanisms of LaFeO₃ (010) surfaces over a range of surface oxygen stoichiometries. For the stoichiometric LaO surface, and for reduced surface terminations, an electron-rich surface is needed for stabilization. By contrast, in the case of the stoichiometric FeO₂ surface and oxidized surface terminations with low-coordinated oxygen atoms, a hole-rich surface is needed for stabilization. The calculations further predict that low coordinated oxygen atoms are more stable on LaO-type surface terminations than on FeO ₂-type surface terminations due to relatively strong electron transfer. In addition to these electronic effects, atomic relaxation is found to be an important contributor to charge compensation, with LaO-type surface terminations exhibiting larger atomic relaxations than FeO₂-type surface terminations. As a result, there is a significant contribution from the sublayers to charge compensation in LaO-type surface terminations.