Self-surfactant effect on Fe/Au(100): place exchange plus Au self-diffusion

In this paper, we report on the submonolayer growth of Fe on Au(100), a system where a monolayer of the substrate floats at the external surface during growth facilitating the layer-by-layer growth of the Fe film. STM and STS demonstrate that this self-surfactant action results from a combination of several processes: fast place exchange between Fe and the Au atoms of the topmost surface layer, anisotropic diffusion of the Au atoms ejected due to the local lifting of the surface reconstruction, and preferential nucleation on the isolated Fe atoms embedded within the surface. The Au atoms diffuse over the surface in a way almost identical to the homoepitaxial growth of Au on Au(100). As a result, stable, reconstructed islands composed of Au atoms are formed and end up burying the deposited Fe. (C) 1998 Elsevier Science B.V. All rights reserved.