Mechanically controlled binary conductance switching of a single-molecule junction Quek, Su Ying Kamenetska, Maria Steigerwald, Michael L. Choi, Hyoung Joon Louie, Steven G. Hybertsen, Mark S. Neaton, J. B. Venkataraman, Latha ; https://orcid.org/0000-0002-6957-6089 Molecular-scale components are expected to be central to the realization of nanoscale electronic devices1,2,3. Although molecular-scale switching has been reported in atomic quantum point contacts4,5,6, single-molecule junctions provide the additional flexibility of tuning the on/off conductance states through molecular design. To date, switching in single-molecule junctions has been attributed to changes in the conformation or charge state of the molecule7,8,9,10,11,12. Here, we demonstrate reversible binary switching in a single-molecule junction by mechanical control of the metal–molecule contact geometry. We show that 4,4'-bipyridine–gold single-molecule junctions can be reversibly switched between two conductance states through repeated junction elongation and compression. Using first-principles calculations, we attribute the different measured conductance states to distinct contact geometries at the flexible but stable nitrogen–gold bond: conductance is low when the N–Au bond is perpendicular to the conducting π-system, and high otherwise. This switching mechanism, inherent to the pyridine–gold link, could form the basis of a new class of mechanically activated single-molecule switches. Springer Nature 2009 info:eu-repo/semantics/article doc-type:article text http://purl.org/coar/resource_type/c_6501 https://research-explorer.ista.ac.at/record/18031 Quek SY, Kamenetska M, Steigerwald ML, et al. Mechanically controlled binary conductance switching of a single-molecule junction. <i>Nature Nanotechnology</i>. 2009;4(4):230-234. doi:<a href="https://doi.org/10.1038/nnano.2009.10">10.1038/nnano.2009.10</a> eng info:eu-repo/semantics/altIdentifier/doi/10.1038/nnano.2009.10 info:eu-repo/semantics/altIdentifier/issn/1748-3387 info:eu-repo/semantics/altIdentifier/e-issn/1748-3395 info:eu-repo/semantics/altIdentifier/arxiv/0901.1139 info:eu-repo/semantics/altIdentifier/pmid/19350032 info:eu-repo/semantics/openAccess