Conductance of individual C₆₀ molecules measured with controllable gold electrodes

We investigated the conductance of C₆₀ molecules using mechanically controllable break-junction electrodes at 10 K in UHV. The molecules are evaporated in situ. With this method, we obtain clean and low-resistance contacts. From the analysis of conductance histograms and differential-conductance (dI∕dV) traces, we deduce the preferred conductance value of a single C₆₀ molecule between gold electrodes to be close to 0.1 G₀. The presence of C₆₀ is evidenced by features in the derivative of the dI∕dV at energies close to the molecular vibration energies. The characteristics of the molecules disappear upon cold working of the junctions.