Conductance of individualC60molecules measured with controllable gold electrodes

Abstract

We investigated the conductance of ${\mathrm{C}}_{60}$ molecules using mechanically controllable break-junction electrodes at $10\mathrm{K}$ 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 ${\mathrm{C}}_{60}$ molecule between gold electrodes to be close to 0.1 $G_0$. The presence of ${\mathrm{C}}_{60}$ 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.