Ab initio calculations of the SrTiO₃(110) polar surface

Results of ab initio Hartree-Fock calculations for the SrTiO₃ (110) polar surface are discussed. We have calculated the surface energies, near-surface atomic displacements for four possible terminations (TiO, Sr, and two kinds of O terminations) as well as Mulliken atomic charges and dipole moments of atoms characterizing their polarization, and the atomic bond populations. We predict a considerable increase of the Ti - O chemical bond covalency near the (110) surface, as compared to both the bulk and the (100) surface. The O-terminated (110) surface has surface energy close to that for (100), which indicates that both (110) and (100) SrTiO₃ surfaces can coexist in polycrystals and perovskite ceramics.