2006/07/31 by Latha Venkataraman, Jennifer E. Klare, Colin Nuckolls +2 · 7 citations
Chemistry · Engineering · Physics and Astronomy · #Break junction #Chemical physics #Chemistry #Condensed matter physics #Conductance #Crystallography #Force Microscopy Techniques and Applications #Materials science #Molecular Junctions and Nanostructures #Molecule #Nanotechnology #Physics #Quantum and electron transport phenomena #Quantum tunnelling #Scanning tunneling microscope #cond-mat.mes-hall
paper · pdf · doi:10.1038/nature05037
accepted to Nature
arxiv created 2006/07/31 · openalex publication_date 2006/08/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
The conductance of a single metal-molecule-metal junction depends critically on the conformations of the molecule. In the simple case of a biphenyl, two phenyl rings linked together by a single C-C bond, the conductance is expected to depend on the relative twist angle between the two rings, with the planar conformation having the highest conductance. A number of different techniques have measured the conductance of metal-molecule(s)-metal junctions. However, the conductance variation from junction to junction has made it difficult to verify even the simplest predictions about how molecules should behave in unimolecular devices. Here, using amine link groups to form single molecule junctions, we show a clear correlation between molecule conformation and junction conductance in a series of seven biphenyl molecules with different ring substitutions that alter the twist angle of the molecules. We find that the conductance for the series decreases with increasing twist angle, consistent with a cosine squared relation predicted theoretically for transport through pi-conjugated systems.