First-principles calculations of SrZrO₃ (001) surfaces

The results of calculations of surface relaxations, rumplings, and charge distribution for the SrZrO₃ (001) surface using ab initio code CRYSTAL and a hybrid description of exchange and correlation are presented. Both SrO and ZrO₂ terminations of the SrZrO₃ (001) surface are considered. On the (001) surfaces all upper and third layer atoms relax inward, while outward relaxations of all atoms in the second layer are found with the sole exception of SrO-terminated SrZrO₃ (001) surface second layer O atom. Calculated surface rumpling for the SrO-terminated SrZrO₃ (001) surface 6.77% of the lattice constant is by a factor of ten larger than the surface rumpling for the ZrO₂-terminated SrZrO₃ (001) surface 0.72% of ao. A considerable increase in the Zr-O chemical bond covalency near the SrZrO₃ (001) surface as compared to the bulk is predicted.