Bistable hysteresis and resistance switching in hydrogen-gold junctions

Current-voltage characteristics of ${\text{H}}_2\text{-Au}$ molecular junctions exhibit intriguing steps around a characteristic voltage of $V_s\approx 40\text{mV}$. Surprisingly, we find that a hysteresis is connected to these steps with a typical time scale $>10\text{ms}$. This time constant scales linearly with the power dissipated in the junction beyond an off-set power $P_s=I{V}_s$. We propose that the hysteresis is related to vibrational heating of both the molecule in the junction and a set of surrounding hydrogen molecules. Remarkably, by stretching the junction the hysteresis’ characteristic time becomes $>\text{days}$. We demonstrate that reliable switchable devices can be built from such junctions.