Surface sites and mobilities of In atoms on a stepped Cu( 100) surface studied at low coverage

The various surface sites of In atoms deposited to a coverage of 0.013 monolayer (ML) onto a stepped Cu(100) surface were determined with low-energy ion scattering (LEIS) as a function of deposition temperature. From the fractions of In atoms occupying different sites, observed in the temperature range 63-300 K, the mobilities of In atoms on the terraces and along the steps were deduced.It was found that during the LEIS measurements with 6 keV Ne ions at temperatures below 120 K Cu adatoms were accumulating at the surface. This is explained by diffusion to the surface of interstitial Cu atoms created in the damage cascades. For temperatures above 120 K these Cu adatoms were found to be mobile on the Cu(100) terraces.