Bistable hysteresis and resistance switching in hydrogen-gold junctions

Current-voltage characteristics of H₂-Au molecular junctions exhibit intriguing steps around a characteristic voltage of Vₛ≈40 mV. Surprisingly, we find that a hysteresis is connected to these steps with a typical time scale >10 ms. This time constant scales linearly with the power dissipated in the junction beyond an off-set power Pₛ=IVₛ. 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 >days. We demonstrate that reliable switchable devices can be built from such junctions.