The researchers show that niobium phosphide can conduct electricity but than copper in films that are only at few atoms thick.
The films can also be created and deposited at sufficiently low temperatures to be compatible with modern computer chip fabrication.
Researchers could help make future electronics more powerful and energy efficient.
“We are breaking a fundamental bottleneck of traditional materials like copper,” said Asir Intisar Khan, who received his doctorate from Stanford and is now a visiting postdoctoral scholar and first author on the paper.
“Our niobium phosphide conductors show that it’s possible to send faster, more efficient signals through ultrathin wires. This could improve the energy efficiency of future chips, and even small gains add up when many chips are used, such as in the massive data centres that store and process information today.”
Niobium phosphide is a topological semimetal, meaning the whole material can conduct electricity, but its outer surfaces is more conductive than its centre.
As a film of niobium phosphide gets thinner, the middle region shrinks but its surfaces stay the same, allowing the surfaces to have a greater share to the flow of electricity and the material as a whole to become a better conductor.
Copper, on the other hand, become worse at conducting electricity once they are thinner than about 50 nanometres.
The researchers found that Niobium phosphide was a better conductor than copper at a thickness of 5 nanometres at room temperature.
“Really high-density electronics need very thin metal connections, and if those metals are not conducting well, they are losing a lot of power and energy,” said Eric Pop, the Pease-Ye Professor in the School of Engineering, a professor of electrical engineering, and senior author on the paper. “Better materials could help us spend less energy in small wires and more energy actually doing computation.”
The niobium phosphide films made by Khan and his colleagues are the first examples of non-crystalline materials that become better conductors as they get thinner.
The researchers deposited the films at 400 degrees Celsius, a temperature that is low enough to avoid damaging or destroying existing silicon computer chips.
“We’ve taken some really cool physics and ported it into the applied electronics world,” Pop said. “This kind of breakthrough in non-crystalline materials could help address power and energy challenges in both current and future electronics.”
