High-conductance states of single benzenedithiol molecules

Conductance of single 1,4-benzenedithiol (BDT) molecules is investigated in a wide range (0-0.3)G(0), exploiting mechanically controllable break junction technique. The authors observed a series of clear conductance steps both in low- (similar to 0.01G(0)) and high-conductance (similar to 0.1G(0)) regimes and corresponding two sets of peak structures in the conductance histograms. The two distinct conductance states are attributable to different Au-S bonding configurations of Au/BDT/Au junctions. The high-bias measurements reveal that the high-conductance state of single BDT molecules is stable up to 1.6 V and prospective for molecular device applications.