American Physical Society, Physical Review B (Condensed Matter), 15(63), 2001
DOI: 10.1103/physrevb.63.155407
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The relaxation of the first seven atomic layers of Cu117 was determined by quantitative low-energy electron diffraction LEED. Intensity versus energy spectra, I(E), were measured for the primary beam at near-normal incidence to the 001 terraces. The data collected cover a cumulative energy range of 3200 eV. Computation of I(E) spectra was performed in the angular momentum representation by considering the surface as a single atomic slab. For the variation of parameters, tensor LEED was applied. The experimental spectra are well reproduced over the entire energy range even for regions of low intensity. The first four layer spacings relax in a way to smooth the surface corrugation, whereby the relative changes d/d 0 amount from top to 13%, 2.0%, 10%, and 7%. This leads to a reduction of the vertical distance between step and corner atoms by 0.13 Å. Comparison with experimental results for Cu115 shows that this modification of the step shape is rather independent of the terrace width. Comparison to theoretical results exhibits, however, some discrepancies with respect to both the expansion/contraction sequence and the amplitudes of the layer relax-ations.