Conductance of Single C60 Molecule Bridging Metal Electrodes

We have developed an ultrahigh vacuum (UHV) system equipped with a mechanically controllable break junction to investigate single molecular conductivity in UHV. Fabrication of the metal nanogap and introduction of molecules into the metal nanogap were performed without breaking vacuum. Using this system, we investigated the electrical conductance of a single C60 molecule bridging between Au or Ag electrodes at 300 K. The conductance of C60 was determined to be 0.2(±0.1) G0 (G0=2e2/h) and 0.5 (±0.1) G0 for the single molecular junction with Au and Ag electrodes, respectively. Insight into the stability of the molecular junction was obtained by analyzing the conductance traces and conductance histograms observed at the transformation process during the stretching.