Molecular signature of highly conductive metal-molecule-metal junctions

The simplicity of single-molecule junctions based on direct bonding of a small molecule between two metallic electrodes makes them an ideal system for the study of fundamental questions related to molecular electronics. Here we study the conductance properties of six different types of molecules by suspending individual molecules between Pt electrodes. All the molecular junctions show a typical conductance of about 1G0 which is ascribed to the dominant role of the Pt contacts. However, despite the metalliclike conductivity, the individual molecular signature is well expressed by the effect of molecular vibrations in the inelastic contribution to the conductance.

This work is part of the research program of the “Stichting FOM,” which is financially supported by NWO. O.T. acknowledges support from IUVSTA-Welch foundation and C.U. acknowledges support through Grant No. MAT2007-65487 and “Consolider” (Grant No. CSD2007-0010) of the Spanish MEC.