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arXiv · 0901.1139

Mechanically-Controlled Binary Conductance Switching of a Single-Molecule Junction

Su Ying Quek·Maria Kamenetska·Michael L. Steigerwald·Hyoung Joon Choi·Steven G. Louie·Mark S. Hybertsen·J. B. Neaton·L. Venkataraman
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Abstract

Molecular-scale components are expected to be central to nanoscale electronic devices. While molecular-scale switching has been reported in atomic quantum point contacts, single-molecule junctions provide the additional flexibility of tuning the on/off conductance states through molecular design. Thus far, switching in single-molecule junctions has been attributed to changes in the conformation or charge state of the molecule. 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 N-Au bond: conductance is low when the N-Au bond is perpendicular to the conducting pi-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.

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Su Ying Quek, Maria Kamenetska, Michael L. Steigerwald, Hyoung Joon Choi, Steven G. Louie, Mark S. Hybertsen, J. B. Neaton, L. Venkataraman. 2009-01-08. Mechanically-Controlled Binary Conductance Switching of a Single-Molecule Junction. https://doi.org/10.1038/nnano.2009.10

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