Highly stable Au atomic contacts covered with benzenedithiol under ambient conditions

The stability of Au atomic contacts under ambient conditions is investigated by measuring the electrical conductance during the self-breaking process. Free standing Au atomic contacts can be kept for more than 100 s after immersion in a 1,4-benzenedithiol (BDT) solution. The average lifetime, that is the amount of time in which the junction remains stable before breaking, is increased from 1.5 s to 12 s due to the metal chemical modification with BDT. By comparing the lifetime of the Au atomic contact covered with BDT and with benzenethiol, we found that the stabilization of the metal atomic contacts stems from the charge transfer from the gold to the molecule. The present results have important implications on the preparation of stable metal atomic contacts and open new directions to fabricate stable nanojunctions at room temperature.