Evaluation of the energy barrier for failure of Au atomic contact based on temperature dependent current-voltage...

We investigated the mechanical stability of single gold atomic contacts at an applied bias voltage of 0-1 V using a nano-fabricated mechanically controllable break junction technique at 300-400 K under ambient conditions. The single atomic contact shows the quantized conductance (G0 = 2e(2)/h) and can carry considerably large current, which results in the current-induced failure of the contact. The contact failure behaviour under the applied bias conditions was studied by statistical analysis of the current-voltage (I-V) curves of the single Au contacts. We demonstrated that, at the elevated temperature of 300-400 K, the current-induced local heating effect is negligibly small and current-induced forces in the contact are responsible for the observed failure of the single gold contacts under the high bias voltage conditions (>0.4 V). Furthermore, based on the temperature dependence of the contact failure behaviour in the I-V curves, the energy barrier of the contact-failure was evaluated to be ca. 0.1 V.