Fractional conductance in hydrogen-embedded gold nanowires.

Interaction of the physically adsorbed molecular hydrogen with a breaking gold nanowire results in additional stable atomic configurations in few atom contacts and appearance of fractional peaks in the conductance histogram. This effect is explained by peculiar dynamic evolution of the hydrogen-embedded nanoconstriction due to competition between tensile and capillary forces. Dimerization within the atomic wire and hydrogen-assisted stabilization of gold dimers results in preferable atomic arrangements with conductivity close to 0.5 and 1.5 of quantum conductance unit G(0)=2e(2)/h.