A groundbreaking paper claiming to show the first room-temperature superconductor has been retracted by the journal Nature due to concerns about its analysis of the data, following allegations the results were manipulated.
Superconductors are materials that exhibit no electrical resistance and are useful for a multitude of applications, including NMR machines, quantum computing, and particle accelerators. However, currently all superconducting materials require very cold temperatures (below 150K) or extremely high pressures. Room-temperature superconductors would revolutionize the way we handle electrical charge and are considered by some to be one of the “holy grails” of chemistry.
The retracted article, written by a team led by Ranga Dias from the University of Rochester, USA, and Ashkan Salamat from the University of Nevada in Las Vegas, USA, was published in October 2020 and seems to have come a little closer to that goal. The team claimed to have found superconductivity in carbonaceous sulfur hydride (CSH) at a temperature of around 288K (15°C), albeit at an intense pressure of 155GPa – around 1.55 million times the pressure. earth’s atmosphere. The result was widely hailed, with suggestions it could win a Nobel Prize, and was seen as heralding a possible new era in superconductors. It has since been viewed more than 100,000 times.
The evidence for superconductivity in the hydride was based on an analysis of magnetic resistance and susceptibility data. However, questions began to emerge in November 2020, when Jorge Hirsch of the University of California, San Diego, USA requested the unprocessed susceptibility data, only to have his request denied. This resulted in Nature adding a disclaimer stating that there were “unstated data access restrictions behind [the] paper’, before the authors then published the raw data in December last year.
Hirsch, along with Dirk van der Marel at the University of Geneva, then began further investigation. Their analysis, says Hirsch, showed that the team could not have produced these results with the method described in the paper, or from the raw data they had obtained. Additionally, the duo said it was not possible to produce the team’s results “without using procedures that can only be characterized as data alteration and manipulation.” By this time, Hirsch, along with Frank Marsiglio of the University of Alberta, Canada, had also questioned the paper’s resistance data, resulting in a paper on “Questions Raised ” in Nature in August 2021.
Now the document has been removed, with Nature noting that “certain key steps in data processing – namely, applied background subtractions… used a non-standard user-defined procedure”. The details of this procedure have not been specified in the document and the validity … has been questioned. The Nature the editors conclude that “we believe that these processing issues undermine confidence in the published magnetic susceptibility dataset, and we retract the article accordingly”.
Hirsch welcomed the decision, but says the retraction notice does not address his claims. ‘Nature sounds like it accepts the authors’ claim that what they call ‘raw data’ is actually data measured in a lab, with lab equipment and a physical sample,” says Hirsch. “In fact, however, we provided Nature clear mathematical evidence that what the authors say is “raw data” is not. Hirsch called on the National Science Foundation, which funded the work, and the University of Rochester to “engage in a thorough review of the facts.”
Responding to world of chemistry, Dias points out that “the retraction request does not question the observed state of physical superconductivity of the CSH material”, only the methodology, and that the team’s results have been replicated both in terms of properties and synthesis and determining the structure used. “Not all of the authors of the article agree with the retraction,” Dias says. “We stand by our work and will resubmit the paper with the raw data plot of susceptibility by Nature‘s recommendation.’