A diamond anvil was used to create the material
Steve Jacobsen/Science Education Resource Center (SERC) at Carleton College
Room-temperature, room-pressure superconductivity has been a central goal of materials science for more than a century, and it may finally have been achieved. If this new superconducting material holds up, it could revolutionize the way our world is powered – but the results are subject to serious scientific scrutiny first.
When a material is superconducting, electricity flows through it with zero resistance, meaning that none of the energy involved is lost as heat. But every superconductor built so far has required extremely high pressures, and most have required similarly high pressures.
Ranga Dias at the University of Rochester in New York and his colleagues claim to have made a material of hydrogen, nitrogen and lutetium that becomes superconducting at a temperature of just 21°C (69°F) and a pressure of 1 gigapascal. This is almost 1000 times the atmospheric pressure at the Earth’s surface, but still much lower than any previous superconducting material. “Suppose you were riding a horse in the 1940s when you see a Ferrari driving by – that’s the level of difference between the previous experiments and this experiment,” says Dias.
To make the material, they placed a combination of the three elements in a diamond anvil—a piece of machinery that compresses samples at extremely high pressures between two diamonds—and pressed it. As the material was compressed, its color changed from blue to red, leading the researchers to call it “red matter.”
The researchers then performed a series of tests that looked at the electrical resistance and thermal capacity of the red matter and how it interacted with an applied magnetic field. All tests have shown the material to be superconducting, they say.
But not all researchers in the field are convinced. “They may have discovered something absolutely groundbreaking and groundbreaking in this work, something that would win a Nobel Prize, but I have some reservations,” says James Hamlin at the University of Florida.
Some of his reservations, and those of other superconductivity researchers, stem from controversy surrounding a 2020 paper by Dias and his team that claimed room-temperature superconductivity and was later retracted by the journal Nature. At the time, some questioned whether the data presented in the paper was accurate and raised questions about how the published data was derived from the raw measurements.
“Until the authors provide answers to these questions that can be understood, there is no reason to believe that [the data] that they publish in this paper reflect the physical properties of real natural samples,” says Jorge Hirsch at the University of California, San Diego.
Part of the reason skepticism is so hard to assuage is that we don’t know enough about red matter to build a theoretical understanding of the mechanism behind its potential superconductivity. “There is still a lot to be done in terms of understanding the exact structure of this material, which is very important to understanding how this material is superconducting,” says Dias. “Hopefully, if we can make it in larger quantities, we’ll get a better understanding of the structure of the material.”
If theorists can figure out exactly how and why this material becomes superconducting, it will both convince researchers that it is in fact a superconductor and could also put the red matter on the path to being industrially produced. “The structures found in this work are probably quite different [from previously confirmed superconducting materials]says Eva Zurek at the University at Buffalo in New York. “The mechanism behind the superconductivity of this compound may be different, but I can’t know for sure because I don’t have a structure to work with.”
If independent teams are able to verify the superconductivity of red matter and understand its structure, it could be one of the most impressive scientific discoveries ever made. A room-temperature, room-pressure superconductor could make the power grid much more efficient and environmentally friendly, supercharge magnetic levitation, and more. “I think there are a lot of technologies that haven’t even been imagined yet that could use room-temperature, room-pressure superconductivity,” Zurek says.
But researchers are not yet dreaming of a superconducting society. “There’s going to be a lot of scrutiny, obviously,” Hamlin says. “I think the difference here from the previous result is that this is at such low pressures that a lot of other teams can see it.” Only a few laboratories around the world have the expensive and complicated diamond anvils capable of reaching the high pressures required by previous superconductivity experiments, but pressure cells that can reach 1 gigapascal are relatively common.
This may be the biggest factor differentiating this work from the retracted 2020 paper. “Their previous work has yet to be replicated by an independent group, but this should be replicated extremely quickly,” says Tim Strobel at the Institute of Science Carnegie in Washington DC. “We’ll do that right away.” If all goes well, this could mark the beginning of an energy revolution.
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