Morphology of monolayer Cu x Au 1-x on Cu(001).

Protruding nanostructure is produced in the single layer of Cu(x)Au(1 - x) surface alloy grown on Cu(001) due to the mismatch strain which has been utilized as a template to tune the magnetic anisotropy of overlays recently. The protrusion network was investigated by in situ scanning tunneling microscopy (STM) combined with low energy electron diffraction (LEED) as a function of the stoichiometry. The measurement revealed the structure of the protrusion and its correlation with the composition. Interestingly, we observed a twin-domain phase of the protrusion when the film approaches the fully hetero-epitaxial range.