Coadsorption study of Pb and Sb on Cu(001) by low energy electron diffraction

Room temperature coadsorption of Pb and Sb on Cu(001) has been studied by low energy electron diffraction (LEED). A p(4×4) structure has been obtained by Pb and Sb at coverages of ∼0.25 and ∼0.125, respectively. This coverage combination is similar to the Pb and Bi study on Cu(001) [1]. This phase is confirmed by clear LEED patterns up to 250 eV. Above this energy some points of p(4×4) phase has been disappeared and only c(4×4) points remain. Based on LEED theory, using computer simulation and similarity of the coverage combination with Pb and Bi study, here a surface alloy model has been proposed and determined. The best-fit structure of the model and its consistency with the experimental results has been discussed in detail.