THE NEW YORK TIMES – A leading physics journal is removing a scientific article published two years ago that described the transformations of a chemical compound when pressed between two pieces of diamond. Such a discovery – and removal – would normally not attract much attention.
But one of the leaders of this research is Ranga P. Dias, a professor in the departments of physics and mechanical engineering at the University of Rochester, in New York. Dias made a big scientific impact earlier this year, announcing the discovery of a supercondutor at room temperature, which could revolutionize computing in unimaginable ways.
At the same time, Dias has become the target of allegations of scientific misconduct, and his supposed discoveries about superconductors remain largely unconfirmed.
The removed article does not involve superconductivity, but rather describes how a relatively common material, manganese sulfide, changes its behavior from an insulator to a metal and then back to being an insulator under increasing pressure.
A complaint that one of the graphics in the article looked suspicious led to the magazine Physical Review Letters to recruit external experts for a more detailed analysis.
The investigation reached disturbing conclusions.
“The findings convincingly confirm the allegations of data fabrication/falsification,” the journal editors wrote in an email to the paper’s authors on July 10.
Ranga Dias, professor at the University of Rochester had article removed from scientific publication
O Times obtained copies of the email and three reports written by the external reviewers. These were not published, but circulated among scientists in the field. The newspaper Campus Times of the University of Rochester and the magazine Nature previously reported on the impending removal.
The reviewers were not convinced by the explanations offered by the authors. Furthermore, additional data requested by the journal to support the article’s claims clearly did not match what had been published.
While Dias continues to defend the work, for some scientists there is now clear evidence of misconduct.
“There is no longer any plausible deniability,” said N. Peter Armitage, a professor of physics and astronomy at Johns Hopkins University in Baltimore, who is among the scientists who have seen the reports. “They sent falsified data. There is no ambiguity whatsoever.”
In recent years, Dias and his colleagues have published a series of spectacular discoveries in top scientific journals.
The last claim came in March. They described, in the magazine Naturea discovery of a superconductor – a material that conducts electricity without losing energy to electrical resistance – which worked at temperatures up to 21 degrees Celsius (although it also required a crushing 145,000 pounds per square inch). Most superconductors need to be cooled to ultra-cold temperatures, which limits their practical use.
Many scientists were skeptical, however, because an earlier paper on superconductors by Dias and his colleagues, also published in Nature, had already been removed. Critics have also found that Dias’ doctoral thesis, completed in 2013 at Washington State University, contains excerpts of plagiarism copied from the work of other scientists.
Several of the authors of the two articles in the Nature also appear in the article of Physical Review Letters on manganese sulfide. Among them are Ashkan Salamat, professor of physics at the University of Nevada, Las Vegas; and Keith V. Lawler, research professor at UNLV.
In a statement provided by his press office, Dr. Dias said, “We express our disappointment regarding the decision made by the PRL editors and duly present our responses to address your questions about the quality of the data in the original article.”
No scientific misconduct occurred and the work did not contain fabrication or manipulation of data, Dias said in the statement. Salamat and Lawler did not respond to requests for comment.
Dias’ adviser said the authors are still in discussions with the magazine’s editors about the next steps.
Representatives of the University of Rochester and the University of Nevada say the schools were aware of discussions about the proposed removal, and if they received notice that the article was withdrawn because of misconduct, they would follow their policies for dealing with such allegations.
Diamond is used in superconductivity experiment Photo: Lauren Petracca / The New York Times
The investigation of Physical Review Letters focused on a graph in the paper that purported to show electrical resistance in manganese sulfide. However, very similar curves also appeared in Dias’ thesis for a completely different material, germanium selenide.
The scientists, called the Alpha, Beta, Delta and Gamma Reviewers, have not been identified. (Alpha and Beta collaborated on a joint report.) When asked for the original experimental data used to generate the graph, Salamat provided a spreadsheet of numbers that further raised suspicions.
All reviewers noted that when they graphed Salamat’s data, they saw no visible kinks in the published graph. “The purported ‘raw data’ appears to be a smoothed and otherwise adulterated version of the data shown” in the journal article, wrote reviewers Alpha and Beta.
In their email, the magazine’s editors wrote: “We view this lack of correspondence and what appears to be a deliberate attempt to obstruct the investigation as another ethical violation.”
The journal told the authors that they could volunteer to correct the article. The journal added that they would remove the article if the authors did not.
After James J. Hamlin, a professor of physics at the University of Florida, denounced the similarities between the graphs, one of the paper’s authors, Simon AJ Kimber, said he immediately recognized problems with the strength data.
“I ordered the correction less than 24 hours later and was not involved in attempts to prevent it,” said Dr. Kimber in an email.
The other authors – Salamat and Dias, in particular – continued to defend the paper, saying that under pressure, both manganese sulfide and germanium selenide act like metals, and therefore it would not be surprising that both materials conduct electricity in a similar way. similar way.
Reviewers weren’t convinced, pointing to minor spots on the curves that appeared to be measurement or noise issues.
“If you want an analogy,” said one of the reviewers, who asked to remain anonymous because the reviewers were not publicly identified, “you could say, oh, a blonde actress looks like every other blonde actress. But those flaws are more like the mole on Marilyn Monroe’s face.”
Finding another blonde actress with an identical mole in the same location on the same face would defy disbelief. This is how the manganese sulfide curve matches that of germanium selenide, this reviewer said.
The conclusion in the Revisor Gama report wryly noted that this correspondence, if true, would herald a great discovery – “a new universality in nature” that different materials under different conditions behave in the same way.
Reviewer Gama added: “It is also conceivable that these findings suggest a departure from standard practices in experimental condensed matter research and require further investigation.”
While the article of Physical Review Letters faces removal, March’s superconductivity claim remains in scientific limbo.
“The group that made this phenomenal claim is a group that is now engaging in careless or even fraudulent data manipulation,” said the reviewer who spoke on condition of anonymity. “It just puts a huge cautionary ring on these results.”
The cloud of suspicion and uncertainty hanging over Dias overshadows previous findings by other scientists, the reviewer said. As of 2014, a research group led by Mikhail Eremets of the Max Planck Institute for Chemistry in Germany has shown that hydrogen-containing compounds are superconducting at surprisingly hot temperatures when squeezed under ultra-high pressures.
“There really does seem to be high-pressure, near-room temperature superconductivity,” the reviewer said. “This is a phenomenal discovery and is widely accepted in the community.”
Dias is not the only researcher looking for a superconductor at room temperature. An article posted by researchers from South Korea a few days ago claims that modifying the mineral apatite produces a superconductor that works at normal temperatures and pressures. /TRANSLATION BRUNO ROMANI
2023-07-27 23:00:00
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