Nature, one of the most prestigious magazines in scientific publishing, on Tuesday withdrawn a high-profile paper he had published in March that claimed the discovery of a superconductor that worked at everyday temperatures.
It was the second paper on superconductors involving Ranga P. Dias, a professor of mechanical engineering and physics at the University of Rochester in upstate New York, that was retracted by the journal in just over a year. It joined an unrelated article that was retracted by another journal in which Dr. Dias was a key author.
The research by Dr. Dias and his colleagues is the latest in a long line of unsuccessful claims for room-temperature superconductors. But the retraction raised uncomfortable questions for Nature about why the journal’s editors published the research after having reviewed and retracted an earlier paper by the same group.
A spokesman for Dr. 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,” the representative said.
First discovered in 1911, superconductors can seem almost magical: they conduct electricity without resistance. However, no known material is superconducting under everyday conditions. Most require ultracold temperatures, and recent advances toward superconductors that operate at higher temperatures require crushing pressures.
A superconductor that operates at everyday temperatures and pressures could be used in MRI scanners, novel electronic devices and levitating trains.
Superconductors unexpectedly became a viral topic on social media over the summer when a different group of scientists, in South Korea, also claimed to have discovered a room-temperature superconductor, called LK-99. Within a couple of weeks, enthusiasm faded after other scientists failed to confirm the superconductivity observations and proposed plausible alternative explanations.
Although it was published in a high-profile journal, Dr. Dias’ claim of a room-temperature superconductor did not spark euphoria like LK-99 did because many scientists in the field already viewed his work with doubt.
In the nature newspaper In a paper published in March, Dr. Dias and his colleagues reported that they had discovered a material (lutetium hydride with some nitrogen added) that was capable of superconducting electricity at temperatures up to 70 degrees Fahrenheit. It still required a pressure of 145,000 pounds per square inch, which is not difficult to apply in a laboratory. The material took on a red hue when squeezed, leading Dr. Dias to nickname it “red matter,” after a substance from a “Star Trek” movie.
Less than three years earlier, Nature published a paper from Dr. Dias and many of the scientists themselves. He described a different material that they said was also a superconductor, although only at crush pressures of nearly 40 million pounds per square inch. But other researchers questioned some of the data in the article. After investigation, Nature agreed, retracting the paper in September 2022 despite the authors’ objections.
In August of this year, the journal Physical Review Letters retracted a 2021 paper by Dr. Dias that described intriguing electrical properties, though not superconductivity, in another chemical compound, manganese sulfide.
James Hamlin, a professor of physics at the University of Florida, told the editors of Physical Review Letters that the curves in one of the paper’s figures describing the electrical resistance in manganese sulfide looked similar to graphs in the doctoral thesis. Dr. Dias who described the behavior of a different matter.
Outside experts recruited by the journal agreed that the data looked suspiciously similar and the article was withdrawn. Unlike Nature’s previous retraction, Dr. Dias’ nine co-authors accepted the retraction. Dr. Dias was the only holdout, maintaining that the article accurately portrayed the research findings.
In May, Dr. Hamlin and Brad J. Ramshaw, a physics professor at Cornell University, sent Nature editors their concerns about the lutetium hydride data in the March paper.
After the retraction of Physical Review Letters, most of the authors of the lutetium hydride paper concluded that the research in their paper was also flawed.
In a letter dated September 8, eight of the 11 authors asked that the Nature article be retracted.
“Dr. Dias has not acted in good faith with respect to the preparation and presentation of the manuscript,” they told Nature editors.
The writers of the letter included five recent graduate students who worked in Dr. Dias’s laboratory, as well as Ashkan Salamat, a professor of physics at the University of Nevada, Las Vegas, who collaborated with Dr. Dias on the two previous retracted articles. Dr. Dias and Dr. Salamat founded Unearthly Materials, a company that was to convert superconducting discoveries into commercial products.
Dr. Salamat, who was president and CEO of the company, is no longer employed there. He did not respond to a request for comment on the retraction.
In the retraction notice published Tuesday, Nature said the eight authors who wrote the letter in September expressed the view that “the published article does not accurately reflect the provenance of the materials investigated, the experimental measurements performed and the processing protocols.” of applied data”. .”
The problems, those authors said, “undermine the integrity of the published article.”
Dr. Dias and two other authors, former students of his, “have not stated whether they agree or disagree with this retraction,” the notice said. A Nature spokeswoman said they did not respond to the proposed retraction.
“This has been a deeply frustrating situation,” Karl Ziemelis, editor-in-chief of physical and applied sciences at Nature, said in a statement.
Mr. Ziemelis defended the magazine’s handling of the article. “Indeed, as is often the case, the highly qualified expert reviewers we selected raised a number of questions about the original submission, which were largely resolved in subsequent revisions,” he said. “This is 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 conducted.”
For Dr. Ramshaw, the retraction provided validation. “When you look at someone else’s work, you always wonder if you’re just seeing things or overinterpreting,” he said.
The disappointments of LK-99 and Dr. Dias’ claims may not deter other scientists from investigating possible superconductors. Two decades ago, a Bell Labs scientist, J. Hendrik Schön, published a series of surprising findings, including new superconductors. Investigations showed that he had invented most of the facts about him.
This did not prevent later great discoveries about superconductors. In 2014, a group led by Mikhail Eremets of Germany’s Max Planck Institute for Chemistry showed that hydrogen-containing compounds superconduct at surprisingly warm temperatures when subjected to ultrahigh pressures. Those findings are still widely accepted.
Russell J. Hemley, a professor of physics and chemistry at the University of Illinois at Chicago, who followed Dr. Eremets’ work with experiments that found another material that was also superconducting under ultrahigh-pressure conditions, continues to believe in the hydride findings. Dr. Dias lutetium. In June, Dr. Hemley and his colleagues reported that they had also measured the apparent disappearance of electrical resistance in a sample that Dr. Dias had provided, and on Tuesday, Dr. Hemley said he remained confident that the findings would be reproduced by other scientists.
After the retraction of Physical Review Letters, the University of Rochester confirmed that it had launched a “thorough investigation” by experts unaffiliated with the school. A university spokeswoman said she had 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 praised Dr. Dias’ research as a breakthrough.
