Growth and surface alloying of Fe on Pt(9 9 7)

The growth of ultra-thin layers of Fe on the vicinal Pt(9 9 7) surface is studied by thermal energy He atom scattering (TEAS) and Auger Electron Spectroscopy (AES) in the temperature range between 175 K and 800 K. We find three distinct regimes of qualitatively different growth type. Below 450 K the formation of a smooth first monolayer, at and above 600 K the onset of bulk alloy formation, and at intermediate temperature 500-550 K the formation of a surface alloy. Monatomic Fe rows are observed to decorate the substrate steps between 175 K and 500 K. The importance of the high step density is discussed with respect to the promotion of smooth layer growth and with respect to the alloying process and its kinetics.