Adsorbate induced manipulation of 1D atomic nanowires: Soliton mediated degradation of long-range order in the Si(553)-Au system

Deposition of Au on vicinal Si(553) surfaces results in the self-assembly of one-dimensional (1D) Au atomic wires. Charge transfer from the Au wire to the Si step edge leads to a chain of Si danglingbond orbitals with a long range ordered threefold periodicity along the steps and infinite interchain interaction perpendicular to the steps. Employing spot-profile analysis low-energy electron diraction (SPA-LEED) we observed a broadening of spot width with time, reflecting the degradation of Si dangling bond chain and Au wire length. Adsorbates were identified as primary source for spot broadening. They force the generation of solitons and anti-solitons which immediately destroy the long-range order along and perpendicular to the steps, respectively. From the temporal evolution of broadening, we conclude that the Au wires are less reactive to adsorption than the Si dangling bond chains.