Growth and alloying of submonolayer Cu on Pt(121211)

A detailed comparative study of Cu growth on the vicinal surface Pt(12 12 11) has been performed with helium atom scattering (HAS) and medium energy ion scattering (MEIS). These techniques are ideally complementary in that HAS is extremely sensitive to the electronic structure of the surface layer, while MEIS accurately probes the atom core structure of the surface. By combining these two techniques it has been possible to measure the initial structure of Cu on the stepped Pt surface and to study how the Cu redistributes across the surface and into the bulk on annealing. The HAS and MEIS data identify two significant diffusion transitions on the surface occurring at temperatures of 450 and 600 K.