Nature ‘unpublishes’ research on superconductor – 11/09/2023 – Science

Nature, one of the most prestigious scientific journals, retracted — in other words, basically reported the “de-publication” — on Tuesday (7) of a highly prominent article that it had published in March. The text announced the discovery of a superconductor that worked at everyday temperatures.

This was the second article on superconductors involving Ranga P. Dias, professor of mechanical engineering and physics at the University of Rochester, in the state of New York, to be retracted by the magazine in just over a year. He joined an article retracted by another magazine, in which Dias was one of the main authors.

The research by Dias and his colleagues is the latest in a long list of room-temperature superconductor claims that have not come to fruition. However, the retraction raised uncomfortable questions for Nature about why the journal’s editors released the research after having already reviewed and retracted an earlier paper by the same group.

A spokesperson for Dias said the scientist denied allegations of research misconduct. “Professor Dias intends to resubmit the scientific article to a journal with a more independent editorial process,” said the representative.

First discovered in 1911, superconductors can seem almost magical — they conduct electricity without resistance. However, no materials are known that are superconductors under everyday conditions. Most require ultra-low temperatures, and recent advances toward superconductors that work at higher temperatures require extreme pressures.

A superconductor that works at everyday temperatures and pressures could be used in MRI machines, innovative electronic devices and levitating trains.

Superconductors went viral on social media over the summer, when a group of scientists in South Korea also claimed to have discovered a room-temperature superconductor called LK-99. Within weeks, excitement waned after other scientists failed to confirm the superconductivity observations and came up with plausible alternative explanations.

Although it was published in a prominent magazine, Dias’ claim about a room temperature superconductor did not cause euphoria like the LK-99, as many scientists in the field already doubted his work.

In the Nature paper published in March, Dias and his colleagues reported that they had discovered a material — lutetium hydride with added nitrogen — capable of superconducting electricity at temperatures of up to 70 degrees Fahrenheit (21.1°C). It was still necessary to apply a pressure of 145 thousand pounds per square inch, which is not difficult to do in a laboratory. The material took on a red hue when compressed, leading Dias to nickname it “reddmatter” in reference to a substance from a “Star Trek” film.

Less than three years earlier, Nature had published a paper by Dias and many of the same scientists. The text described a different material that they claimed was also a superconductor, albeit only under extreme pressures of nearly 40 million pounds per square inch. However, other researchers questioned some of the article’s data. After an investigation, Nature agreed and retracted the paper in September 2022, despite the authors’ objections.

In August, the journal Physical Review Letters retracted a 2021 paper by Dias that described intriguing electrical, though not superconducting, properties in another chemical compound, manganese sulfide.

James Hamlin, a professor of physics at the University of Florida, informed the editors of Physical Review Letters that the curves in one of the paper’s figures describing electrical resistance in manganese sulfide appeared similar to graphs in Dias’ doctoral thesis describing the behavior of a different material.

Independent experts hired by the magazine agreed that the data looked suspiciously similar, and the article was retracted. Unlike the previous Nature retraction case, all nine of Dias’s co-authors agreed to the retraction. Dias was the only one to object and stated that the article accurately presented the results of the research.

In May, Hamlin and Brad J. Ramshaw, professors of physics at Cornell University, sent their concerns about the lutetium hydride data in the March paper to the editors of Nature.

After retraction by Physical Review Letters, most of the authors of the lutetium hydride paper concluded that their paper’s research was also flawed.

In a letter dated September 8, 8 of the 11 authors asked for the Nature article to be retracted.

“Dias did not act in good faith in relation to the preparation and submission of the manuscript,” they told Nature’s editors.

The letter’s authors included five recent graduate students who worked in Dias’ lab, as well as Ashkan Salamat, a professor of physics at the University of Nevada, Las Vegas, who collaborated with Dias on the two previously retracted papers. Dias and Salamat founded Unearthly Materials, a company aimed at turning superconductivity discoveries into commercial products.

Salamat, who was the company’s president and CEO, is no longer an employee there. He did not respond to a request for comment on the retraction.

In the retraction notice published on Tuesday (7), Nature said that the eight authors who wrote the letter in September expressed the opinion that “the published article does not accurately reflect the provenance of the materials investigated, the experimental measurements carried out and the applied data processing protocols”.

The problems, these authors said, “undermine the integrity of the published article.”

Dias and two other authors, former students of his, “did not state whether they agree or disagree with this retraction,” the notice said. A Nature spokesperson said they had not responded to the retraction.

“This has been a deeply frustrating situation,” Karl Ziemelis, editor-in-chief of applied and physical sciences at Nature, said in a statement.

Ziemelis defended the magazine’s handling of the article. “Indeed, as is so common, the highly qualified expert reviewers we selected raised several issues about the original submission, which were largely resolved in subsequent reviews,” he said. “That’s how peer review works.”

He added: “What the peer review process cannot detect is whether the article, as written, accurately reflects the research as it was carried out.”

For Ramshaw, the retraction was validation. “When you’re investigating someone else’s work, you always wonder if you’re just seeing things or interpreting too much,” he said.

Following the retraction of the Physical Review Letters, the University of Rochester confirmed that it had begun a “comprehensive investigation” by experts not affiliated with the university. A university spokesperson said it has no plans to make the results of the investigation public.

The University of Rochester removed YouTube videos it produced in March in which university officials touted Dias’ research as a breakthrough.