Electrically Driven Molecular Archimedes Screw Achieves Reversible Rotation Between Gold Electrodes

Researchers at the Weizmann Institute positioned a custom helical molecule synthesized at Copenhagen between two gold electrodes fabricated by electromigration. Application of bias drove electron flow that transferred angular momentum, producing sustained rotation whose handedness tracked voltage sign. Quantum simulations performed at Augsburg on the LiCCA cluster mapped transmission probability versus torsion angle and showed that the rotating conformations open high-conductance channels absent in the static geometry. The 2011 surface-mounted motors required an STM tip for both power and readout; the present device operates while covalently anchored at both ends, satisfying a prerequisite for integration into solid-state circuits. Conductance modulation of two orders of magnitude supplies an intrinsic electrical readout of motor state without auxiliary optical or mechanical probes. Scaling laws that have already produced billion-transistor chips now confront the stochastic regime of single-molecule mechanics. Successful directional control at this length scale therefore tightens the link between synthetic chemistry and nanoelectronic architecture, yet thermal fluctuations at room temperature remain unquantified in the reported data. Next required milestones are on-chip wiring density above 10^6 devices per square centimeter and operational lifetimes exceeding 10^9 rotations.