Electronic Transparence of a SingleC60Molecule

We report the first study of electrical contact with an individual molecule (${\mathrm{C}}_{60}$). Using a scanning tunneling microscope tip, the electrical current $I$ flowing as a function of tip displacement $s$ towards the molecule is investigated [ $I\left(s\right)$ characteristics]. The tunneling current increases approximately exponentially with tip displacement in the tunnel regime, but this behavior changes significantly as contact is established. From the $I\left(s\right)$ data and calculations for ${\mathrm{C}}_{60}$ we determine an apparent electrical resistance of 54.80 M $\Omega$ for the junction at “tip contact.” In the Landauer formalism, this value is a measurement of the electronic transparence $2.35\times {10}^{-4\mathrm{}}$ of the molecule under the tip.