Ab initio calculations of SrTiO₃, BaTiO₃, PbTiO₃, CaTiO₃ and BaZrO₃ (001) and (011) surfaces

I present results of calculations of surface relaxations and rumplings for the (001) and (011) surfaces of BaZrO₃ and ATiO₃ perovskites (A = Sr, Ba, Pb and Ca) using a hybrid B3PW description of exchange and correlation. The (001) surface energies of AO, TiO₂ and ZrO₂ terminations are found to be comparable with each other for all five materials. The surface energies for BaZrO₃, SrTiO₃, BaTiO₃, PbTiO₃ and CaTiO₃ (011) surfaces for all terminations are considerably larger than for (001) surfaces. We predict a considerable increase in the Ti-O (Zr-O) chemical bond covalency near the (011) surface as compared both to the bulk and to the (001) surface.