First-principles study of the (0 0 1) surface of cubic SrZrO3

Density functional calculations have been used to investigate the (0 0 1) surface of cubic SrZrO3 with both SrO and ZrO2 termination. Surface structure and electronic structure have been obtained. The SrO surface is found to be similar to its counterpart in SrTiO3, while there are marked differences between the ZrO2 and TiO2 terminations in SrZrO3 and SrTiO3, respectively, concerning surface relaxation and rumpling. For the ZrO2-terminated surface of SrZrO3, the covalency of the interaction between the outmost Zr and the O beneath is enhanced as a result of their bond contraction. The band gap reduction and the presence of the surface states are also discussed in relation with the behavior of the electrostatic potential.