Measurements of contact specific low-bias negative differential resistance of single metalorganic molecular junctions

Negative differential resistance (NDR) behaviors of single molecule junctions composed of a thiol-terminated Ru(ii) bis-terpyridine (Ru(tpy-SH)2) molecule sandwiched between two gold electrodes are measured using a specifically modified scanning probe microscope break junction technique (SPMBJ) at room temperature. The low-bias (0.623 ± 0.135 V) NDR observed for one of the three conductance groups is contact specific and is caused by a bias induced electrode-molecule coupling changes.