Repository logo

Optical probes of molecules as nano-mechanical switches

Published version

Change log



Abstract: Molecular electronics promises a new generation of ultralow-energy information technologies, based around functional molecular junctions. Here, we report optical probing that exploits a gold nanoparticle in a plasmonic nanocavity geometry used as one terminal of a well-defined molecular junction, deposited as a self-assembled molecular monolayer on flat gold. A conductive transparent cantilever electrically contacts individual nanoparticles while maintaining optical access to the molecular junction. Optical readout of molecular structure in the junction reveals ultralow-energy switching of ∼50 zJ, from a nano-electromechanical torsion spring at the single molecule level. Real-time Raman measurements show these electronic device characteristics are directly affected by this molecular torsion, which can be explained using a simple circuit model based on junction capacitances, confirmed by density functional theory calculations. This nanomechanical degree of freedom is normally invisible and ignored in electrical transport measurements but is vital to the design and exploitation of molecules as quantum-coherent electronic nanodevices.



Article, /639/925/927/998, /639/925/927/1021, /639/925/357/354, /639/624/399/1098, /639/624/400/1021, /119, /119/118, /120, /147/3, /128, /132/122, /140/133, article

Journal Title

Nature Communications

Conference Name

Journal ISSN


Volume Title



Nature Publishing Group UK
RCUK | Engineering and Physical Sciences Research Council (EPSRC) (EP/G060649/1, EP/L027151/1, EP/G037221/1, NanoDTC)
EC | Horizon 2020 Framework Programme (EU Framework Programme for Research and Innovation H2020) (THOR 829067)
Leverhulme Trust (ECF-2018-375)