LETTER TO THE EDITOR: Atomistic simulation of ? surface relaxation

The (001) surface relaxation of the cubic perovskite 0953-8984/10/21/003/img8 crystal has been studied using the shell model. The positions of atoms in several surface layers embedded in the electrostatic field of the remainder of the crystal are calculated. We show that 0953-8984/10/21/003/img9, and 0953-8984/10/21/003/img10 ions in six near-surface layers are displaced differently from their crystalline sites which leads to the creation of so-called surface rumpling, a dipole moment, and an electric field in the near-surface region. Calculated atomic displacements are compared with LEED experimental data.