Surface Segregation of Ni(110)-0.8%Au by Scanning Tunneling Microscope

The surface segregation of Ni(110)-0.8%Au has been studied by Scanning Tunneling Microscope (STM). Flat Ni(110)-(1x1) surfaces were observed by STM, resolving individual atomic rows, before Au segregation to the surface. After annealing above 650 Degrees C, the alloy surface was covered by Au atoms which form a 21 07 reconstruction. The segregated Au layer formed hexagonal chains. Incommensurate Au atoms in "bridges" between the hexagonal chains were also observed. These results illustrate the critical role of the STM in elucidating the surface structure structure of complex systems.