Science

Physicists are advancing in the race for superconductivity at room temperature

Diamond Anvil Cell
Written by boustamohamed31

Diamond Anvil Cell

A team of physicists at UNLV’s Nevada Extreme Conditions Laboratory (NEXCL) used a diamond anvil cell, a research device similar to the one pictured, in their research to reduce the pressure needed to observe a material capable of superconductivity at room temperature temperature. Credit: Image courtesy of NEXCL

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

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

International headlines were in 2020 with the opening of superconductivity at room temperature for the first time by UNLV physicist Ashkan Salamat and colleague Ranga Dias, a physicist at the University of Rochester. To achieve the feat, the scientists chemically synthesized a mixture of carbon, sulfur and hydrogen first into a metallic state and then even more into a superconducting state at room temperature, using extremely high pressure – 267 gigapascals – conditions you’d only find in nature near the center of the earth.

Fast forward less than two years, and the researchers are now able to complete the feat at just 91 GPa—roughly a third of the pressure originally reported. The new findings were published as a preliminary journal article Chemical communications this month.

Super discovery

By fine-tuning the composition of carbon, sulfur and hydrogen used in the initial breakthrough, the researchers are now able to produce a material at lower pressures that retains its superconducting state.

“These are pressures at a level difficult to understand and evaluate outside the laboratory, but our current trajectory shows that it is possible to achieve relatively high superconducting temperatures at consistently lower pressures – which is our ultimate goal,” said the study’s lead author Gregory Alexander Smith, graduate student researcher with UNLV Nevada Extreme Conditions Laboratory (NEXCL). “After all, if we want to make devices useful for societal needs, then we need to reduce the pressure required to create them.”

Although the pressure is still very high — about a thousand times what you would experience at the bottom of the Mariana Trench in the Pacific Ocean — it continues to aim for a near-zero goal. It’s a race that is gathering pace exponentially at UNLV as researchers gain a better understanding of the chemical relationship between the carbon, sulfur and hydrogen that make up the material.

“Our knowledge of the relationship between carbon and sulfur is advancing rapidly, and we are discovering ratios that lead to remarkably different and more efficient reactions than originally observed,” said Salamat, who directs UNLV’s NEXCL and contributed to the latest study. “To observe such diverse phenomena in such a system just shows the richness of Mother Nature. There is so much more to understand, and each new advance brings us closer to the precipice of everyday superconducting devices.”

The holy grail of energy efficiency

Superconductivity is a remarkable phenomenon, first observed more than a century ago, but only at remarkably low temperatures, which preempted any thought of practical application. It wasn’t until the 1960s that scientists theorized that the feat might be possible at higher temperatures. The 2020 discovery by Salamat and colleagues of a room-temperature superconductor excited the scientific world in part because the technology supports electrical flow with zero resistance, meaning that energy passing through a circuit can be conducted indefinitely and without power 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 shows no signs of slowing down, and costs are increasing in part due to the US power grid losing an estimated $30 billion a year due to the inefficiencies of current technology,” Salamat said. “For societal change, we need to lead with technology and the work being done today, I believe, is 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 of the US and beyond.

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

Reference: “Carbon content drives high-temperature superconductivity in carbon disulphide below 100 GPa” by G. Alexander Smith, Innes E. Collings, Elliot Snyder, Dean Smith, Sylvain Petitgirard, Jesse S. Smith, Melanie White, Elise Jones, Paul Ellison , Keith W. Lawler, Ranga P. Dias, and Ashkan Salamat, 7 Jul 2022, Chemical communications.
DOI: 10.1039/D2CC03170A

Smith, the lead author, is a former UNLV undergraduate 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 with UNLV; Ranga Dias, Elliot Snyder, and Elise Jones of the University of Rochester; Ines E. Collings of the Swiss Federal Laboratories for Materials Science and Technology, Sylvain Petitgirard of ETH Zurich; and Jesse S. Smith of Argonne National Laboratory.

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