IIT-M Faculty Makes Key Inputs to Global Study on Molecular Electronics
Dr. Anil Kumar Singh, assistant professor in the department of physics at IIT-M, is a corresponding author and the principal experimental contributor. The team includes researchers from India, Israel, Germany, Denmark and China.
An international research team, including an IIT-Madras faculty member, has demonstrated how electric current can drive the rotation of a single molecule with the motion, increasing electrical conduction by up to 100 times. The findings, published in 'Nature', could inform the development of future nanoscale electronic devices.
The study demonstrates a feedback mechanism between molecular motion and electrical transport at the atomic scale. It has potential applications in molecular switches and components whose electrical properties can be controlled through movement.
Dr. Anil Kumar Singh, assistant professor in the department of physics at IIT-M, is a corresponding author and the principal experimental contributor. The team includes researchers from India, Israel, Germany, Denmark and China.
The researchers used a spiral-shaped molecule called helicene, suspended between two gold electrodes. When voltage was applied, the molecule moved through a cyclic sequence of configurations. In all 122 cases where the direction of transitions could be determined, the researchers observed the same sequence. Reversing the voltage polarity reversed the sequence, showing that molecular motion could be controlled electrically.
Beyond a threshold voltage, the team observed a sharp increase in current. The molecule shifted from moving between preferred orientations to continuous rotation, passing through configurations that allowed electrons to flow more easily. This increased electrical conduction through the molecular junction by up to approximately 100 times. The threshold could also be adjusted by stretching or compressing the junction.
Dr Singh said molecular motion could do more than result from electrical transport; it could also facilitate electron flow by enabling the molecule to access configurations with higher electrical conductance.
The experiments were conducted at 4.2 kelvin, or approximately minus 269 degrees Celsius, during Dr Singh's research tenure at the Weizmann Institute of Science in Israel. He cautioned that the work was a proof of concept, not a technology ready for practical use, and that further research was needed to establish reliable operation under practical conditions.