IIT Madras faculty joins global study on electrically controlled molecular rotation

An Indian Institute of Technology Madras (IIT Madras) researcher has contributed to an international study by showing how electrical current can control the rotation of a single molecule. He has also shown how this movement can increase the flow of electricity.

Anil Kumar Singh, assistant professor at IIT Madras , is a corresponding author and the principal experimental contributor to the study. The research involved scientists from India, Israel, Germany, Denmark and China.

Elaborating on this research, Anil Kumar Singh said, “An exciting aspect of this work is that molecular motion is not merely a consequence of electrical transport; it can also facilitate the passage of electrons through the molecule. By demonstrating this feedback between rotation and electrical conduction in a single-molecule junction, we have taken a step towards understanding how mechanical motion and electronic function can be coupled at the atomic scale.”

The study, published in the 'Nature' journal, might help researchers develop future nanoscale electronic components whose electrical properties can be controlled through molecular movement.

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The researchers have also observed that electrical current increased by up to 100 times when the molecule shifted from stepwise movement to continuous rotation. During rotation, the molecule passed through configurations that allowed electrons to flow more easily.

The team found that gently stretching or compressing the molecular junction could also change the conditions under which this increase in current occurred.

Talking about the current status of this research, Anil Kumar Singh added, “This is a fundamental proof-of-principle demonstration, rather than a technology ready for practical use. The experiments were performed at cryogenic temperatures, and further research will be needed to establish reliable operation under practical conditions.”

Molecular machines perform specific tasks in response to stimuli such as light, chemicals, or electricity. Understanding how their movement affects electrical conduction could support the development of molecular-scale switches and other electronic components. The experiments were conducted at a temperature of 4.2 kelvin, or about minus 269 degrees celsius.