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What if superconductors could work at room temperature?

07/24/17 - BOSTON, MA. - Arun Bansil, University Distinguished Professor in the Department of Physics, poses for a portrait at Northeastern University on July 24, 2017. Photo by Matthew Modoono/Northeastern University

Everything we know in the world is made up of basic materials. Superconductors, which represent one class of these materials, are remarkably good at conducting electricity—as long as they’re kept very, very cold. But if researchers could find a way to develop room-temperature superconductors, we’d see “a new technological revolution,” according to Arun Bansil, University Distinguished Professor of Physics at Northeastern.

In a paper published recently in Communications Physics, a Nature publication, Bansil and his colleagues describe a discovery that brings us closer to that elusive feat—what he described as the “holy grail” of the field. For the first time, researchers were able to model the behavior of electrons, which are responsible for superconductors’ ability to conduct electricity. Understanding this puzzling phenomenon, Bansil said, could be the critical step necessary toward designing superconductors that work at room temperature.

Understanding superconductors
Superconductors can transmit electrical current with absolutely no loss of energy. If scientists can develop them to function at room temperature, they may one day replace anything requiring electricity—including entire power grids.

To make a new material, researchers must first understand and explain how the material’s parent compounds behave using mathematical models. “For example, if we can model and understand the working of an engine, then we are able to design a more efficient car,” Bansil said.

The base material for the first superconductor ever discovered is lanthanum copper oxide, which is an insulator, meaning it does not conduct electricity. But current mathematical models for superconductors predict lanthanum copper oxide to be a metal.

The problem lies in the inability of these models to explain how the parent compound transitions from an insulator to a metal. The transition occurs when researchers add strontium atoms to the lanthanum copper oxide.

“Suddenly it become the world’s best conductor—a superconductor,” Bansil said. For the first time, his team was able to model both the insulating state and the transition to the metallic state when strontium is added to the parent compound, he explained.

“Once we know how to model things correctly, then we can predict how the behavior of the material will change when we change composition or other features of the material and thus we are in position to design higher temperature superconductors,” Bansil said.

‘Major breakthrough’
John Perdew, a professor of physics and chemistry at Temple University who was not involved in the research, called the paper a “major breakthrough” that could lead to the discovery of new superconducting materials that can operate at higher temperatures. Those materials could eventually enable the creation of energy-saving power lines, Perdew said.

“If you have superconducting power lines, then you don’t have any loss. Whatever power you generate at the power station, you transmit the same amount to its destination,” Perdew said.