REHOVOT, ISRAEL — October 22, 2026 — Invented more than two millennia ago, the machine known as the Archimedes screw is a giant corkscrew of sorts, with a spiral blade that rotates around its axis to pump water. In recent decades, this ancient invention has also been used as a turbine in hydroelectric power plants. Now, researchers at the Weizmann Institute of Science and their colleagues have created a molecular version of the famous screw and discovered a surprising relationship between electric current and rotational motion: When the current causes the molecule to rotate, the rotation, in turn, can enhance electrical conduction.
In a study published today in Nature, researchers from the lab of Prof. Oren Tal of Weizmann’s Chemical and Biological Physics Department suspended a single helical organic molecule between two gold electrodes at a temperature close to absolute zero. When they applied a voltage between the electrodes, they detected cyclical jumps in the current flowing through the molecule; the sequence of the jumps indicated rotation in one direction. When the scientists reversed the direction of the current, the sequence of jumps was also reversed, indicating that the molecule was rotating in the opposite direction. But the biggest surprise came when they increased the voltage: Above a certain threshold, the current flowing through the molecule surged by up to a hundredfold.
“These findings demonstrate a new operating principle for nanomachines."
According to the researchers’ calculations, this sharp increase occurs when the molecule goes from sequential rotational jumps to continuous rotation, allowing electrons to pass through it more easily. “We also discovered that the threshold at which the current starts to increase sharply can be controlled by stretching or compressing the molecule, much like changing the angle of the blades in a turbine,” Tal says.
A new twist on Archimedes screw: Simulation of a helical molecule rotating between two gold electrodes under the influence of an electric current flowing through it. The molecule’s rotation, in turn, enhances its electrical conduction.
“These findings demonstrate a new operating principle for nanomachines: The electric current drives the molecule’s rotation, while the rotation, in turn, enhances electrical conduction, allowing more current to flow through the molecule under the applied voltage.”
The study was led by Dr. Anil Kumar Singh, who conducted the experiments at the Weizmann Institute during his postdoctoral research under Tal’s supervision. Singh is now a faculty member at the Indian Institute of Technology Madras. The project was carried out in collaboration with the research groups of Prof. Fabian Pauly at the University of Augsburg, Germany; Profs. Michael Pittelkow and Per Hedegård at the University of Copenhagen, Denmark; and Prof. Jing-Tao Lü at the Huazhong University of Science and Technology, China. Pittelkow’s group synthesized the molecules, while the other international collaborators performed the theoretical calculations.
Prof. Oren Tal is head of the Helen and Martin Kimmel Center for Nanoscale Science. His research is supported by Dita & Yehuda L. Bronicki; and the Harold Perlman family.