Electron Transfer Dynamics of Bistable Single-Molecule Junctions

We present transport measurements of single-molecule junctions bridged by a molecule with three benzene rings connected by two double bonds and with thiol end-groups that allow chemical binding to gold electrodes. The I−V curves show switching behavior between two distinct states. By statistical analysis of the switching events, we show that a 300 meV mode mediates the transition between the two states. We propose that breaking and reformation of a S−H bond in the contact zone between molecule and electrode explains the observed bistability.