2008/03/05 by Mark S. Hybertsen, Latha Venkataraman, Jennifer E. Klare +3 · 2 citations
Engineering · Physics and Astronomy · #Force Microscopy Techniques and Applications #Molecular Junctions and Nanostructures #Quantum and electron transport phenomena #cond-mat.mes-hall
paper · pdf · doi:10.1088/0953-8984/20/37/374115
Invited paper for forthcoming special issue of Journal of Physics: Condensed Matter
arxiv created 2008/03/05 · openalex publication_date 2008/08/26 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
A comprehensive review is presented of single-molecule junction conductance measurements across families of molecules measured while breaking a gold point contact in a solution of molecules with amine end groups. A theoretical framework unifies the picture for the amine-gold link bonding and the tunnel coupling through the junction using density functional theory based calculations. The reproducible electrical characteristics and utility for many molecules is shown to result from the selective binding between the gold electrodes and amine link groups through a donor-acceptor bond to undercoordinated gold atoms. While the bond energy is modest, the maximum force sustained by the junction is comparable to, but less than, that required to break gold point contacts. The calculated tunnel coupling provides conductance trends for all 41 molecule measurements presented here, as well as insight into the variability of conductance due to the conformational changes within molecules with torsional degrees of freedom. The calculated trends agree to within a factor of 2 with the measured values for conductance ranging from 10(-7)G(0) to 10(-2)G(0), where G(0) is the quantum of conductance (2e(2)/h).