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 have finally been achieved. If this new superconducting material holds up, it could revolutionise the way our world is powered – but the results are headed for serious scientific scrutiny first.
When a material is superconductive, electricity flows through it with zero resistance, which means none of the energy involved is lost as heat. But every superconductor made so far has required extraordinarily high pressures, and most have required similarly high temperatures.
Ranga Dias at the University of Rochester in New York and his colleagues claim to have made a material from hydrogen, nitrogen and lutetium that becomes superconductive at a temperature of just 21°C (69°F) and a pressure of 1 gigapascal. That is nearly 10,000 times the atmospheric pressure on Earth’s surface, but still far lower pressure than any previous superconducting material. “Let’s say you were riding a horse in the 1940s when you see a Ferrari driving past you – that’s the level of difference between previous experiments and this one,” says Dias.
To make the material, they placed a combination of the three elements into a diamond anvil – a piece of machinery that compresses samples to extraordinarily high pressures between two diamonds – and squeezed. As the material was compressed, its colour changed from blue to red, leading the researchers to nickname it “red matter”.
The researchers then ran a series of tests examining the red matter’s electrical resistance and heat capacity, and how it interacted with an applied magnetic field. All the tests pointed towards the material being superconductive, they say.
But not all researchers in the field are convinced. “Perhaps they have discovered something absolutely groundbreaking and earth-shattering 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, are due to controversy surrounding a 2020 paper by Dias and his team, which claimed room-temperature superconductivity and was later retracted by the scientific 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 those questions that can be understood, there is no reason to believe that [the data] they are publishing in this paper reflect the physical properties of real physical samples either,” says Jorge Hirsch at the University of California San Diego.
Part of the reason that scepticism 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 possible superconductivity. “There’s still a lot to be done in terms of understanding the exact structure of this material, which is very crucial to understanding how this material is superconducting,” says Dias. “We’re hoping if we can make it in larger quantities we’ll get a better understanding of the material structure.”
If theorists can figure out exactly how and why this material becomes superconductive, it will both go a long way towards convincing researchers that it is, in fact, a superconductor, and it could also put red matter on the road to being produced industrially. “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 this compound’s superconductivity might be different, but I can’t know for sure because I don’t have a structure to work off of.”
If independent groups are able to verify red matter’s superconductivity and figure out its structure, this could be one of the most impactful scientific findings ever. A room-temperature, room-pressure superconductor could make the electrical power grid far more efficient and environmentally friendly, supercharge magnetic levitation and far more. “I think there are a lot of technologies that haven’t even been imagined yet that could use room-temperature, room-pressure superconductivity,” says Zurek.
But researchers aren’t dreaming about a superconducting society yet. “There’s going to be a lot of scrutiny, obviously,” says Hamlin. “I think that the difference here from the previous result is that this is at such low pressures that a lot of other groups can look at this.” 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 commonplace.
That may be the biggest factor differentiating this work from the retracted 2020 paper. “Their previous work still hasn’t been reproduced by an independent group, but this one should be reproduced extremely quickly,” says Tim Strobel at the Carnegie Institution for Science in Washington DC. “We’re going to do this right away.” If all goes well, this could mark the beginning of an energy revolution.
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