Epitaxial Growth of Au on Ni(110) by Scanning Tunneling Microscopy

Epitaxial Growth of Au on Ni(110) has been studied by Scanning Tunneling Microscopy (STM). Equilibrium overlayer was obtained by surface segregation of dilute Ni(110) alloy. At coverages of 0.7 ML, only commensurate Au atoms were grown, forming a (7x4) reconstruction with c(2x4) subunit. At coverages of >0.8 ML, Au atoms appeared at incommensurate sites, with the bulk Au nearest neighbor distance. The observed structure is an example of Stranski-Krastanov growth. These results illustrate the critical role of the STM in elucidating the surface of complex systems.