Template Assisted Nucleation of Cobalt and Gold Nano-clusters on an Ultrathin Iron Oxide Film

Being the basic building blocks for nano-magnetic and nano-catalytic devices, regular arrays of nano-clusters play a crucial role in modern nanotechnology. One of the possible fabrication methods of periodic nanostructures consists in exploiting nano-patterned substrates as templates for the self-assembly of the deposited atoms. Here, we have investigated the templating properties of a Moiré superlattice formed at the interface between a FeO(111)-like ultrathin film and a Ni/Fe(001) substrate. Co and Au, representative of elements with high and low oxygen affinity, respectively, have been deposited on the iron oxide film. Scanning tunneling microscopy reveals that Co nucleates preferentially along the corrugated regions of the Moiré superstructure, forming stripes with high aspect ratio. On the other hand, Au atoms nucleate randomly distributed three-dimensional islands on the FeO(111) surface.