‘Revolutionary’ Blue Crystal Sparks Hope of Room Temperature Superconductivity

sciencehabit shares a report from Science Magazine: Has the quest for room temperature superconductivity finally succeeded? Researchers at the University of Rochester (U of R), who previously were forced to retract a controversial claim of room temperature superconductivity at high pressures, are back with an even more spectacular claim. This week in Nature they report a new material that superconducts at room temperature — and not much more than ambient pressures. “If this is correct, it’s completely revolutionary,” says James Hamlin, a physicist at the University of Florida who was not involved with the work. A room temperature superconductor would usher in a century-long dream. Existing superconductors require expensive and bulky chilling systems to conduct electricity frictionlessly, but room temperature materials could lead to hyperefficient electricity grids and computer chips, as well as the ultrapowerful magnets needed for levitating trains and fusion power. […]

On February 22, [physicist Ranga Dias] and his colleagues doubled down on their original claim. In a preprint posted on arXiv they reported synthesizing a new version of CSH that superconducts at a slightly lower 260 K, but at only about half the previous pressure. “This should clear up any questions regarding CSH,” says co-author Russell Hemley, an x-ray crystallographer at the University of Illinois, Chicago, who helped determine the material’s structure. Now comes the even more promising substance: nitrogen-doped lutetium-hydride (LNH). To make it, Dias’s team loaded a thin lutetium foil in a diamond vise and injected a mix of hydrogen and nitrogen gas. By ramping the pressure up to 2 gigapascals (nearly 20,000 times atmospheric pressure) and baking the mix at 200C for up to 3 days, they forged a bright blue crystalline fleck, one that survived even after the pressure was eased.

When they dialed the pressure back up to as little as 0.3 gigapascals, the blue fleck turned pink as the electrical resistance plunged to zero. The substance reached a peak superconducting temperature of 294 K-7-degrees warmer than the original CSH and truly room temperature — at pressures of 1 gigapascal. Magnetic measurements also showed the sample repelled an externally applied magnetic field, a hallmark of superconductors. The paper, the authors say, went through five rounds of review. Given the U of R group’s recent retraction, many physicists won’t be easily convinced. “I think they will have to do some real work and be really open for people to believe it,” Hamlin says. Jorge Hirsch, a physicist at the University of California, San Diego, and a vociferous critic of the earlier work, is even more blunt. “I doubt [the new result], because I don’t trust these authors.”

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