Smallest superconductor spells hope for cooler electronics in future

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London, March 31 (ANI): A team of scientists has developed a one-molecule-wide wire, which in other words is the smallest superconductor that can conduct electricity without any heat loss, thus spelling hope for cooler electronics in the future.

Heat is produced by wires and components in proportion to their electrical resistance, and that increases at smaller scales.

According to a report in New Scientist, the new wire, developed by Saw-Wai Hla's group at Ohio University in Athens, is a superconductor, a type of material through which current flows with zero resistance and hence no heat loss.

The scientists made four-molecule-long wires - the smallest superconducting structure yet reported.

The nanoscopic wires were made by placing a mixture of a large organic molecule and a salt of the metal gallium on a super-clean sheet of silver.

The molecules in the mixture then automatically arrange themselves into long strings or wires, with the organic molecules on the outside and the salt in the centre.

The researchers cooled this set-up to 5 kelvin (-268 degree Celsius), and used a scanning tunnelling microscope (STM) to feel for the tiny wires and test their conductive properties.

In isolation, neither the gallium salt nor the organic compound conducted electricity, but Hla and colleagues found evidence that the wires they made from the two together have superconducting characteristics.

An STM works by applying a voltage between the microscope's tip and the material it is scanning, and then monitoring the change in current.

When Hla's team varied the voltage and monitored the conductance, a plot of one versus the other showed a V-shaped "conducting gap" that gradually disappeared as the temperature was raised to 15 kelvin - behaviour characteristic of a superconductor.

This superconducting gap was found in nanowires with as few as four salt molecules, but not in nanowires that were only three molecules long.

"Finding out why will help explain how such tiny structures can perform as superconductors," Hla said. (ANI)

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