Archimedes screw-inspired molecular machine boosts electrical conductivity

JERUSALEM, Oct. 22 (Xinhua) -- An international team of researchers has developed a molecular machine inspired by the ancient Archimedes screw, revealing a new way to connect mechanical movement and electrical conduction at the molecular scale, Israel's Weizmann Institute of Science said on Thursday.

The Archimedes screw is a simple machine that moves water uphill by rotating a screw-like blade (helical surface) inside a hollow pipe.

Inspired by the ancient invention, the molecular structure features a helical molecule produced by stretching it between two gold tips. The researchers can stretch or compress the molecular screw by adjusting the distance between the gold electrodes.

According to the findings published in the latest issue of Nature, the molecule rotates when a voltage is applied, and the rotating molecule conducts electricity significantly better than a stationary one. Above a certain voltage level, the electrical current is increased by up to 100 times.

The researchers' calculations showed that the positions the molecule avoids when at rest conduct electricity best, and rotation makes these positions accessible.

Based on the calculations, researchers developed a simplified model that reproduced the experimentally observed rotation and current increase.

The researchers highlighted the close collaboration between experiment and theory across several countries. The study drew together scientists from research institutes in Israel, Germany, Denmark and China.

Molecular machines are inspired by biological motors that convert energy into movement. The field gained international recognition with the 2016 Nobel Prize in Chemistry, awarded for the design and synthesis of molecular machines.

The new findings could inform future research into molecular electronics, spintronics and microfluidic systems, holding potential to provide a way to investigate physical processes at the atomic scale. ■