Surface rumples and band gap reductions of cubic BaZrO₃ (001) surface studied by means of first-principles calculations

Electronic properties of the (001) surface of cubic BaZrO_3 with BaO and ZrO_2 terminations have been studied using first-principles calculations. Surface structure, partial density of states, band structure and surface energy have been obtained. We find that the largest relaxation appears in the first layer of atoms, and the relaxation of the BaO-terminated surface is larger than that of the ZrO_2-terminated surface. The surface rumpling of the BaO-terminated surface is also larger than that of the ZrO_2-terminated surface. Results of surface energy calculations reveal that the BaZrO_3 surface is likely to be more stable than the PbZrO_3 surface.