Multilayer relaxation of the Al(210) surface

Abstract

The surface structure of Al(210) has been determined by means of a systematic minimization of the discrepancy between experimental low-energy electron diffraction intensity-energy spectra and spectra calculated using multiple-scattering theory, as a function of the structural and nonstructural variables of the calculations. The experimental data base consists of intensity-energy spectra for 14 symmetry-inequivalent diffracted beams, measured at normal incidence and at 135 K in the energy range 40–340 eV. The surface structure is found to exhibit an oscillatory, multilayer relaxation. The relaxations Δ$d_i$ and Δ$r_i$ of the first five interlayer spacings and registries with respect to the corresponding bulk values are determined to be Δ$d_1$=-(16±2)%, Δ$d_2$=-(1±3)%, Δ$d_3$=+(9 ±3)%, Δ$d_4$=-(4±4)%, Δ$d_5$=-(1±5)%, and Δ$r_1$=(0±3)%, Δ$r_2$=-(3±3)%, Δ$r_3$=+(2±3)%, Δ$r_4$=-(2±4)%, Δ$r_5$=-(1±5)%.