ALLOYING AT THE CO PT(111) INTERFACE - A STUDY BY CRYSTALLOGRAPHIC LOW-ENERGY-ELECTRON DIFFRACTION/

After depositing a single atomic layer of cobalt on the Pt(111) surfac e, annealing at 600 K leads to the formation of a surface alloy of sta ble composition and structure. This phase was examined by crystallogra phic low energy electron diffraction finding that of the two topmost l ayers the first layer contains 20 at% of cobalt and the second one 80 at% of cobalt. No significant amounts of cobalt could be detected belo w the second atomic layer from the surface.