Less than two years ago, the world of science was shocked by the discovery of a material capable of superconducting at room temperature. Now, a team of physicists at the University of Nevada Las Vegas (UNLV) has once again upped the ante by reproducing this 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 how energy is transported.
It was the international headlines in 2020 by discovering room temperature superconductivity for the first time Written by UNLV physicist Ashkan Salamat and colleague Ranga Dias, a physicist at the University of Rochester. To achieve this feat, the scientists made a chemical mixture of carbon, sulfur and hydrogen first into a metallic state, and then into a superconducting state at room temperature using extremely high pressure – 267 gigapascals – conditions you find only in nature near the center of the Earth.
Fast-forward in less than two years, and the researchers are now able to complete the feat at just 91 gigapascals — roughly a third of the pressure initially reported. The new findings were published as an advance article in the journal chemical communication This month.
By detailed tuning of the carbon, sulfur and hydrogen composition used in the original breakthrough, the researchers are now able to produce a material under low pressure that maintains its state of superconductivity.
“These are pressures at a level that are difficult to understand and assess outside the laboratory, but our current course shows that it is possible to achieve high high conduction temperatures at relatively low pressures – and that is our ultimate goal,” said study lead author Gregory Alexander Smith. Postgraduate student researcher with UNLV Extreme Conditions Laboratory in Nevada (Nexel). “At the end of the day, if we want to make devices useful to society’s needs, we have to reduce the pressure needed to create them.”
Although the pressures are still very high – about a thousand times higher than what you might experience at the bottom of the Mariana Trench in the Pacific Ocean – they continue to race towards a target approaching zero. It’s a steamy race at UNLV as researchers gain a better understanding of the chemical relationship between carbon, sulfur and hydrogen that makes up the material.
“Our knowledge of the relationship between carbon and sulfur is advancing rapidly, and we are finding ratios that lead to significantly different and more efficient responses than initially observed,” said Salamat, who directs NEXCL at UNLV and contributed to the latest study. “Observing such different phenomena in a similar system only shows the richness of Mother Nature. There is so much 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 fascinating phenomenon first observed over a century ago, but only at significantly lower temperatures any idea of practical application has been ruled out. Only in the 1960s did scientists hypothesize that this feat might be possible at even higher temperatures. The 2020 discovery by Salamat and colleagues of a room-temperature superconductor excited the world of science in part because the technology supports electrical flow without resistance, meaning that power passing through an electrical circuit can be conducted infinitely and without energy loss. This could have major implications for energy storage and transmission, supporting everything from better cell phone to a more efficient power grid.
“The global energy crisis is showing no signs of slowing down, and costs are rising in part due to the US power grid losing nearly $30 billion annually due to the inefficiency of current technology,” Salamat said. “For social change, we need to lead with technology, and the work that’s happening today is, I believe, at the forefront of tomorrow’s solutions.”
According to Salamat, the properties of superconductors could support 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 increases high-temperature superconductivity in carbon-sulfur hydride below 100 GPa” by J. Alexander Smith, Innes E. Collings, Elliot Snyder, Dean Smith, Sylvain Pettigerard and Jesse S. Ellison, Keith F. 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 PhD student in chemistry and research with NEXCL. Additional 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; Ines E. Collings with the Swiss Federal Laboratories for Materials Science and Technology, Sylvain Pettigerard with ETH Zurich; and Jesse S. Smith of Argonne National Laboratory.