Physicists advance in the race for room-temperature superconductivity

Less than two years ago, the scientific world was shocked by the discovery of a material capable of superconducting at room temperature. Now, a team of physicists from the University of Nevada, Las Vegas (UNLV) has once again upped the ante by repeating the feat at the lowest pressure ever recorded.

To be clear, this means that science is closer than ever to a usable, repeatable material that could one day revolutionize the way energy is transmitted.

It was the international headlines in 2020 by discovering Room temperature superconductivity for the first time Written by UNLV physicist Ashkan Salamat and colleague Ranja Dias, a physicist at the University of Rochester. To achieve this feat, the scientists made a chemical mixture of carbon, sulfur and hydrogen first in a metallic state and then into a superconducting state at room temperature using extremely high pressure – 267 gigapascals – conditions you’d only find in nature near the center of Earth.

Less than two years later, the researchers are now able to achieve this feat at just 91 gigapascals, about a third of the pressure originally reported. The new findings were published in a preliminary article in the journal chemical communication This month.

great discovery

By adjusting the combination of carbon, sulfur and hydrogen used in the initial penetration, the researchers are now able to produce a material under low pressure that maintains its superconducting state.

“These are pressures at a level that is difficult to understand and assess outside the lab, but our current path shows that it is possible to achieve relatively high conductivity high temperatures at consistently low pressures – and that is our ultimate goal.” , said the study. The lead author, Gregory Alexander Smith, is a graduate student researcher at UNLV. Extreme Conditions Laboratory in Nevada (Nexel). “Ultimately, if we want to make devices useful for society’s needs, we need to reduce the pressure to create them.”

Although the pressures are still very high – about a thousand times higher than what you feel at the bottom of the Mariana Trench in the Pacific Ocean – they continue to rush towards a target approaching zero. It’s a race that is growing exponentially at UNLV as researchers gain a better understanding of the chemical relationship between carbon, sulfur and hydrogen that makes up the material.

said Salamat, who leads NEXCL at UNLV and contributed to the latest study. Observing such different phenomena in a similar system shows the richness of Mother Nature. There is a lot to understand, and each new advance brings us closer to the brink of everyday superconducting devices. »

The Holy Grail of Energy Efficiency

Superconductivity is a remarkable phenomenon that was first observed over a century ago, but only at significantly lower temperatures did any idea of ​​practical application preempt. Until the 1960s, scientists speculated that this feat might be possible at even higher temperatures. The 2020 discovery by Salamat and colleagues of the room-temperature superconductor intrigued the scientific world in part because the technology supports electrical flow without resistance, which means that power flowing through a circuit can be infinitely driven without energy loss. This could have major implications for energy storage and transmission, supporting everything from better cell phone batteries to a more efficient power grid.

“The global energy crisis is showing no signs of abating and costs are rising in part because of the US power grid, which loses an estimated $30 billion annually due to inefficiencies in current technology,” Salamat said. “For societal change we need to be at the forefront of technology, and the work being done today is, I believe, at the forefront of tomorrow’s solutions.”

According to Salamat, the properties of superconductors could underpin a new generation of materials that could fundamentally change the energy infrastructure in the United States and beyond.

“Imagine harnessing energy in Nevada and sending it across the country without any energy loss,” he said. “This technology could make that possible one day.”

Reference: “Carbon content leads to high temperature superconductivity in carbonic sulfur hydride below 100 GPa” by J. , Keith V. Lawler, Ranja B. Dias and Ashkan Salamat, 7 July 2022, Available here. chemical communication.
DOI: 10.1039 / D2CC03170A

Smith, lead author, is a former UNLV researcher in Salamat’s lab and a current chemistry student and PhD researcher at NEXCL. Other study authors include Salamat, Dean Smith, Paul Ellison, Melanie White and Keith Lawler of UNLV. Ranga Dias, Elliot Snyder and Elise Jones of the University of Rochester; Collings of the Federal Laboratory for Testing of Materials and Technology, Sylvain Pettigerhard of the Federal Institute of Technology in Zurich; and Jesse S. Smith of Argonne National Laboratory.

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