Sites, mobilities, and cluster formation of In atoms on a stepped Cu(100) surface

The surface sites in In atoms deposited to a coverage of 0.013 monolayer onto a stepped Cu(100) surface were determined with low-energy ion scattering. This was done for various deposition temperatures in the range 63--300 K. The mobilities of In atoms on the terraces and along steps were deduced from the deposition-temperature dependence of the fractions of In atoms occupying different sites. It was found that, with increasing temperature, In adatoms first migrate to step edges to form one- and two-dimensional clusters and then are incorporated into the terraces at near-substitutional sites.