One-dimensional Mn nanostructures formed on vicinal Au(1 1 1) surfaces

One-dimensional (1D) nanostructures have been fabricated with Mn adatoms on vicinal Au(1 1 1) surfaces and characterized by scanning tunneling microscopy. Dosed Mn atoms are adsorbed at lower corners of {1 1 1} steps, and Mn adlayers grow in a step-flow growth mode on (1 1 1) terraces. Atomic resolution STM images reveal that the 1D Mn adlayers exhibit various superstructures depending on the coverage. At the beginning, Mn adatoms form 1D monatomic rows along the steps showing the same spacing as the Au substrate lattice. Once the second rows are attached, the 1D nanostructures show twofold periodicity. As the coverage is increased, a structural phase transition occurs and a mixture of a 2×1 structure and a √3×√3-R30° structure appears. The growth mechanism is discussed in terms of adsorption energy, surface energy and diffusivity, comparing with the growth of other transition metals.