Surface alloy model of p(2 × 2)Sb/Cu(0 0 1) from LEED I/V data

We report on the re-determination of the structure of p(2 × 2)Sb/Cu(0 0 1) from measured LEED I/V data. The structure solution is performed in two steps. First an approximate “image” of the surface structure model is found by an application to the measured data of the recently-proposed Phase and Amplitude Recovery and Diffraction Image Generation Method (PARADIGM). This reveals that the p(2 × 2) structure is formed by the protrusion of one atom out of four in the outermost surface layer. Since an Sb atom is larger than one of Cu, this suggests a possibility that the p(2 × 2) structure is formed by Sb substitution for one out of four Cu atoms in the outermost layer. Second, a tensor LEED refinement of the model suggested by the PARADIGM yields the same dominant top-layer substitutional model proposed in the earlier LEED study, but with a much lower reliability factor, making much less likely an admixture of other surface phases.