Structure of Segregated Au Layers on Ni(110)-0.8% Au Alloy by Scanning Tunneling Microscopy.

The structure of the Au segregated Ni(110)-0.8% Au surface has been studied by scanning tunneling microscopy. The observed reconstructions, including 7d sub 110 and 5d sub 110 periodicities with a c(2x4) subunit, are shown to be consistent with the observed LEED pattern. Two different kinds of Au structures, commensurate atomic chains and incommensurate closed-packed atomic rows, were observed. A model for the nucleation and growth of the segregated layer is proposed.