Controversial University of Rochester physicist Ranga P. Dias faces a potential third retraction of a paper related to his work on room-temperature superconductors in a year, after the co-authors of a study published in March 2023 have asked for it to be retracted following concerns over the integrity of its data.
The paper, published by the journal Nature, reported that a compound called lutetium hydride becomes a superconductor with the addition of a small amount of nitrogen atoms and high pressure.
Letter to Nature
Against the backdrop of an investigation ongoing by the University of Rochester into Dr. Dias’s work, his coauthors – mostly graduate students at the time the work was conducted – wrote a letter to Tobias Rödel, a senior editor at Nature, The Wall Street Journal reported on September 26.
In the letter, the group urged the journal to retract the paper because, The Wall Street Journal said it added, the paper had misrepresented measurements of electrical resistance and heat capacity – which are used to infer that a material is superconducting. The group also wrote that its members had notified Dr. Dias of these concerns but that he had “largely dismissed” them as well as that “some of us were instructed by Dr. Dias not to probe further into the issues raised and/or not to worry about such concerns”.
Dr. Dias told the newspaper, “I have never engaged in the fabrication, manipulation, or misrepresentation of data in any of my research endeavors.”
The newspaper also reported that at least six of the co-authors of the paper had received an email earlier in September from Dr. Dias in which he threatened them with a defamation lawsuit if they didn’t “cease and desist” their correspondence with editors at Nature.
Another critique
On May 2, two physicists who were unidentified at the time also submitted a note to Nature in which they criticised the results described in the published paper. Science reported on September 27 that they were James Hamlin (University of Florida) and Brad Ramshaw (Cornell University).
In their note, Drs. Hamlin and Ramshaw had also raised concerns about the electrical resistance plot. In their paper, Dias et al. had written that the resistance was measured with some noise and that the noise had been subtracted later, leaving only the resistance signal. But critics have alleged that the subtraction removed more than just noise and that the signal left behind was anomalous.
Two other retractions
At least one attempt to replicate the findings of the lutetium hydride paper, by Russell Hemley (University of Illinois Chicago) claimed to have found evidence that the material becomes a superconductor in the circumstances described in the March 2023 paper. But independent experts have said its “resistance measurements may be flawed,” according to Science, even as Dr. Hemley has stood by his findings.
On September 26, 2022, Nature had retracted another paper of a study led by Dr. Dias that purported to show that a compound of carbon, sulphur, and hydrogen became a superconductor, over concerns about data of the material’s magnetic susceptibility. In August 2023, Physical Review Letters retracted another paper led by Dr. Dias in which his group reported superconductivity in manganese sulphide. The paper was retracted again over concerns with the electrical resistance measurement.
Unearthly Materials
Dr. Dias has founded a company, called Unearthly Materials, to commercialise his findings. A superconductor that can work in ambient conditions is expected to revolutionise a plethora of fields and industries, including high-energy physics, electrical engineering, and medical diagnostics. But the slew of retractions is expected to increase scrutiny of its plans and the $16.5 million it has raised from investors, per The New York Times.
The journal Nature is also under the lens for its vetting process, which has thus far allowed two problematic papers to get through before facing the prospect of retraction.
