Determination of the structure of Cu{1 0 0}-p(32×2)R45°–Sn by dynamical LEED

The geometrical structure of 0.50 ML Sn adsorbed on Cu{1 0 0} surface has been studied using Symmetrized Automated Tensor LEED. At this coverage, a p(32×2)R45° ordered surface structure is formed. The favoured structure is a substitutional surface alloy, that includes a missing row reconstruction. This structure might have originated a from c(2 × 2) superstructure. The p(32×2)R45° phase is formed by bringing pairs of Sn atoms together in the Cu{1 0 0}-c(2 × 2)–Sn alloyed top layer and removing every third row of copper in the top layer. The two in-equivalent tin atoms in the first layer are buckled towards the solid-vacuum interface by 0.39/0.27 ± 0.07 Å with respect to the first layer copper atoms. The buckling between the Sn atoms is 0.12 ± 0.08 Å. The lateral displacement of Sn atoms is of magnitude 0.26 ± 0.10 Å. The first interlayer spacing is expanded by 4% with respect to the bulk value. Pendry reliability factor has been used to measure the level of agreement between theory and experiment giving a moderate value of 0.26 for the favoured structure.