Abstract
For more than two millennia, Archimedean screws have been used for water pumping and, more recently, as turbines in hydroelectric power stations[1]. Their helical-blade structure, essential to their function, is also found in chiral molecules and nanostructures, where injected electric current has been proposed to generate torque-mediated rotation[2,3]. Here, we present a torque-driven molecular machine with a rotor actuated by electric current and conductance enhanced by its rotation. Suspending a helicene molecule between two electrode tips, we show that an applied voltage induces cyclic molecular motion with 100% directional preference that can be inverted by the voltage’s polarity. Above a voltage threshold, the current through the rotating molecule is significantly enhanced, and the enhancement onset is tuned by stretching or compressing the helical molecule. Such effects were absent in previous helical molecular junctions, likely due to structural and operational differences[4–6]. Calculations show that molecular rotation by current-induced forces explains both the observed cyclic motion and current enhancement. This mechanism predicts a transition from stepwise to continuous rotation at a threshold voltage, yielding a current increase as rotation allows adopting highly conducting configurations not accessible at rest. Our work introduces a prototype for a new class of torque-driven molecular machines with perfect rotor unidirectionality and significant current modulation.
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Author information
Authors and Affiliations
Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
Anil Kumar Singh & Oren Tal
Department of Physics, Indian Institute of Technology Madras, Chennai, Tamil Nadu, India
Anil Kumar Singh
Institute of Physics and Center for Advanced Analytics and Predictive Sciences, University of Augsburg, Augsburg, Germany
León Martin, Yuta Ito & Fabian Pauly
Department of Chemistry, University of Copenhagen, Copenhagen Ø, Denmark
Matea Sršen, Stephan Korsgaard Pedersen, Fadhil Suleiman Kamounah & Michael Pittelkow
Niels Bohr Institute, University of Copenhagen, Copenhagen N, Denmark
Freja Schou Guttesen & Per Hedegård
School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, PR China
Bing-Zhong Hu & Jing-Tao Lü
Wuhan Institute of Quantum Technology, Wuhan, PR China
Jing-Tao Lü
Sino-Danish College, University of Chinese Academy of Sciences, Beijing, PR China
Freja Schou Guttesen & Per Hedegård
Authors
- Anil Kumar Singh
- León Martin
- Matea Sršen
- Freja Schou Guttesen
- Bing-Zhong Hu
- Yuta Ito
- Stephan Korsgaard Pedersen
- Fadhil Suleiman Kamounah
- Fabian Pauly
- Michael Pittelkow
- Jing-Tao Lü
- Per Hedegård
- Oren Tal
Corresponding authors
Correspondence to Anil Kumar Singh, Fabian Pauly, Michael Pittelkow, Jing-Tao Lü, Per Hedegård or Oren Tal.
Supplementary information
Supplementary Information (download PDF )
Supplementary Information describing the synthesis and characterization of the dithioacetyl-functionalized [13]helicene. It details the fabrication and measurement of single-molecule Au-helicene-Au junctions and presents experimental analyses of their operation as molecular machines, together with control experiments and a discussion of alternative explanations for the observed effects. It also includes density functional theory calculations of the molecular junction structure and rotational potential landscape, as well as quantum electronic transport calculations. Finally, it presents a microscopic theoretical framework that explains the current-induced torque, molecular rotation, and current enhancement underlying the observed behaviour.
Supplementary Video 1 (download MP4 )
Stochastic jump of the molecular rotor from one potential minimum to the next, driven by fluctuations and current-induced torque. Here, the work done by friction exceeds the work done by the current-induced torque. The molecular junction video is based on density functional theory calculations of snapshot configurations at different rotation angles.
Supplementary Video 2 (download MP4 )
Free rotation of the molecular rotor along the tilted potential, driven by fluctuations and current-induced torque. Here, the work done by the current-induced torque is greater than that done by friction. The molecular junction video is based on density functional theory calculations of snapshot configurations at different rotation angles.
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Cite this article
Singh, A.K., Martin, L., Sršen, M. et al. Current-Driven Molecular Machine with Rotation-Enhanced Conductance. Nature (2026). https://doi.org/10.1038/s41586-026-11312-x
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DOI: https://doi.org/10.1038/s41586-026-11312-x