  Room temperature conductance-elongation curves of gold atomic wires are
measured using a Scanning Tunnelling Microscope Break Junction technique.
Landauer's conductance plateaus are individually identified and statistically
analysed. Both the probabilities to observe, and the lengths of the two last
plateaus (at conductance values close to 2e2/h and 4e2/h) are studied. All
results converge to show that the occurrence of these two conductance plateaus
on a conductance-elongation curve are statistically independent events.
