Abstract
We have investigated the conductance of a single 1,3-benzenediamine or 1,4-benzenediamine molecule bridging between Au electrodes, in order to discuss the effect of the end group position on the conductance of the single disubstituted benzene molecular junction. The conductance of the single 1,3-benzenediamine molecular junction was determined to be 5×10-3 (±1×10-3) G0 (G0=2e2/h). This conductance value was smaller than the previously reported conductance value of the 1,4-benzenediamine single molecular junction (0.01 G0) measured under the same experimental condition by a factor of two. The contribution of the quantum interference effect on conductance of the single benzenediamine molecular junction was discussed. In the single 1,3-benzenediamine molecular junction, two electron paths around the benzene ring would interfere destructively due to the difference in the path length, leading to a decrease in conductance of the single molecular junction.
