A team of 11 scientists reported in March in the journal Nature that they had discovered a room-temperature superconductor. Eight of those scientists have now asked Nature to retract their paper.
That brings them face to face with the man who led the investigation: Ranga P. Dias, a professor of mechanical engineering and physics at the University of Rochester in New York. In recent years, Dr. Dias has made several extraordinary scientific claims, but he has also been embroiled in a series of accusations of scientific misconduct.
The retraction request will add to scrutiny of Dr. Dias and Unearthly Materials, a company Dr. Dias founded to turn superconductivity discoveries into commercial products. Unearthly Materials has raised $16.5 million from investors.
It also raises questions about how editors at Nature, one of the scientific world’s most prestigious journals, vet submissions and decide which ones are worthy of publication. Nature had already published and withdrawn an earlier paper by Dr. Dias’ group describing a different putative superconductor.
Superconductors are materials that can conduct electricity without any electrical resistance, and one that works under everyday conditions could find wide use in the transmission of electricity and for powerful magnets used in MRI machines and future fusion reactors. The superconductors discovered to date require ultracold temperatures.
In the Nature article, Dr. Dias and his co-authors described how lutetium hydride (a material made of lutetium, a silvery-white metal, and hydrogen) acquired new electronic properties when a small amount of nitrogen was added. When compressed to a pressure of 145,000 pounds per square inch, the material not only changed color, from blue to red (leading Dr. Dias to give it the nickname red matter), but it also became a superconductor. , capable of effortlessly transporting electricity at temperatures up to 70 degrees Fahrenheit, the scientists said in the Nature article.
Skeptics almost immediately questioned the findings, prompting Nature to reexamine the research.
The co-authors said Dr. Dias kept most of them out of the post-publication review loop for several months.
In their letter to Tobias Rödel, senior editor of Nature, dated September 8, the co-authors described what they considered significant flaws in the research and said they believed that “Dr. Dias has not acted in good faith with respect to the preparation and presentation of the manuscript.
The Wall Street Journal reported in Tuesday’s letter.
Among the writers of the letter were five recent graduate students who worked in Dr. Dias’ laboratory. They said they raised concerns during the preparation of the scientific paper. “Those concerns included clearly misleading and/or inaccurate representations in the manuscript,” they wrote.
They said that Dr. Dias made some changes, but that “our concerns were largely dismissed by Dr. Dias, and some of us were instructed by Dr. Dias not to further investigate the issues raised and/or not worry about such concerns.”
The letter said the graduate students felt limited in what they could say at the time because they relied on Dr. Dias for academic and financial support.
Among the signatories of the letter requesting a retraction was Ashkan Salamat, a physics professor at the University of Nevada, Las Vegas, and co-founder of Unearthly Materials, who serves as president and CEO. That was a change from May, when Dr. Salamat and Dr. Dias defended the paper in a rebuttal to concerns raised by other scientists.
Dr. Salamat did not respond to requests for comment. A spokesman for Dr. Dias said Dr. Salamat was no longer an employee of Unearthly Materials, but remained a shareholder.
The only authors of the March paper who did not sign the letter were Dr. Dias, a graduate student who is currently a member of its research group, and a former undergraduate student who, according to his LinkedIn profile, now works at Unearthly Materials.
Before sending the letter, Dr. Dias urged the authors to reconsider their decision. “I am obligated to defend myself and communicate to you my request that you cease and desist from signing and/or sending the proposed letter,” he wrote In a letter shared on social networks by the science journalist Dan Garisto. Dr. Dias’ spokesperson confirmed the contents of the letter.
However, the retraction request was sent to Nature. The Wall Street Journal reported that Dr. Rödel responded in an email: “We absolutely agree with his request that the article be withdrawn.”
Karl Ziemelis, editor-in-chief of physical sciences at Nature, said in a statement: “We are currently carefully investigating concerns related to the reliability of the data in this paper. “We can also confirm that we are corresponding with the authors regarding all concerns.”
He added: “We hope to take action in the near future.”
A retraction of the lutetium hydride paper would be Dr. Dias’ third retraction in the last year.
In 2020, Dr. Dias and his collaborators described in a paper, also published in Nature, a different material that was superconducting at room temperature, but only at crushing pressures similar to those found near the center of the Earth.
After some scientists questioned the data in the 2020 paper, Nature conducted a review and then retracted the paper in September 2022 despite objections from Dr. Dias and all the other authors.
In August, the journal Physical Review Letters retracted another of Dr. Dias’ papers, one published in 2021 that described the electronic transformations of manganese sulfide under changing pressure. Critics again pointed out data that seemed suspicious, and after outside reviewers took a closer look, the magazine’s editors agreed.
“The findings convincingly support allegations of data fabrication/falsification,” the editors wrote in an email to the paper’s authors in July. Nine of the ten authors of the manganese sulfide paper accepted the retraction. Dr. Dias was the only one who resisted, insisting that the work contained no manipulation or invention.
A similar sequence of events is repeated with the role of lutetium hydride. Brad J. Ramshaw, a professor of physics at Cornell University, was involved in the review that led to the retraction of the 2020 Nature article.
After the lutetium hydride paper was published, Dr. Ramshaw noticed oddities in the electrical resistance measurements.
He reached out to James J. Hamlin, a physics professor at the University of Florida, who had previously published an analysis of the 2020 superconductivity paper. In early May, Dr. Hamlin and Dr. Ramshaw wrote their concerns about the data of lutetium hydride and sent them to Nature.
Without revealing the identities of Dr. Hamlin and Dr. Ramshaw, concerns were sent to Dr. Dias and in late May, Dr. Dias and Dr. Salamat sent their rebuttal. On June 26, Dr. Hamlin and Dr. Ramshaw responded to the rebuttal, detailing how the procedure described in Dr. Dias’ article to subtract a background signal in resistance measurements could not have produced the graphs shown in Article.
“I don’t know anyone in the field of superconductivity who would do what they did with the data,” Dr. Ramshaw said in an interview.
Nature recruited four arbitrators to weigh the arguments. They largely sided with Dr. Hamlin and Dr. Ramshaw. One referee wrote that Dr. Dias and Dr. Salamat “did not provide satisfactory answers to several questions” and questioned why the authors “are unwilling or unable to provide clear and timely answers.”
In the September 8 letter, the co-authors said that most of them did not learn of the concerns until July 6, after Dr. Dias and Dr. Salamat had already responded.
The co-authors’ letter described problems with the data or analysis of several of the figures in the paper. The letter also revealed that almost all of the lutetium hydride samples were purchased commercially (some contained some nitrogen impurities) and were not manufactured in Dr. Dias’ laboratory using the recipe described in the Nature article.
In April 2022, graduate students approached Dr. Dias with their concerns and he responded that they could remove their names as authors or they could allow the article to continue.
“At the time, neither option seemed sustainable given that Dr. Dias was in control of our personal, academic and financial circumstances, as our mentor and supervisor,” the letter writers said.
Dr. Dias’ spokesperson said that Dr. Dias never bullied his students. “All discussions were open and available to all co-authors,” the spokesperson said. “The co-authors made collective decisions about publication.”
