Structural study of the Cu{1 0 0}–p(2 × 2)-Sb surface alloy using low energy electron diffraction

The deposition of 0.25 ML Sb on clean Cu{1 0 0} at room temperature results in a p(2 × 2) low energy electron diffraction (LEED) pattern. The structure of the Cu{1 0 0}–p(2 × 2)-Sb phase has been determined using tensor LEED. The results show that despite the large size mismatch between Sb (atomic radius=1.450 Å) and Cu (atomic radius=1.278 Å), a surface alloy is formed in which Sb atoms substitute Cu atom in the outermost layer. Sb is found to ripple outward from the surface by 0.56 ± 0.05 Å. The second and deeper Cu layers are found to be close to their bulk values.