On 2020-10-14, Nature published the paper “Room-temperature superconductivity in a carbonaceous sulfur hydride” which reported (from the abstract):
superconductivity in a photochemically transformed carbonaceous sulfur hydride system, starting from elemental precursors, with a maximum superconducting transition temperature of 287.7 ± 1.2 kelvin (about 15 degrees Celsius) achieved at 267 ± 10 gigapascals. The superconducting state is observed over a broad pressure range in the diamond anvil cell, from 140 to 275 gigapascals, with a sharp upturn in transition temperature above 220 gigapascals.
Other researchers working in the area identified apparent flaws in the work and/or were unable to repeat the experiment. They were unable to obtain the raw data behind the paper from its authors. On 2021-08-30, Nature annotated the paper with a statement:
Editor’s Note: The editors of Nature have been alerted to undeclared access restrictions relating to the data behind this paper. We are working with the authors to correct the data availability statement.
On 2022-02-15, the following additional note was added.
Editor’s Note: The editors of Nature have been alerted to concerns regarding the manner in which the data in this paper have been processed and interpreted. Nature is working with the authors to investigate these concerns and establish what (if any) impact they will have on the paper’s results and conclusions. In the meantime, readers are advised to use caution when using results reported therein.
On 2022-09-26 the hammer came down, and Nature issued a full retraction of the paper, accompanied by a news article the following day, “Stunning room-temperature-superconductor claim is retracted”.
A high-profile study in which researchers claimed to have observed the first true room-temperature superconductor has been retracted.
Physicist Ranga Dias at the University of Rochester in New York State and his collaborators stirred interest but also caution with a 2020 Nature paper1 that reported the creation of a superconductor that worked at an unprecedented temperature of 15 ˚C. The material was a mix of carbon, hydrogen and sulfur, but to conduct electricity without resistance it had to be squeezed between two diamond tips to 2.6 million times greater than atmospheric pressure.
Dias’s team “used a non-standard, user-defined procedure” in subtracting noise from experimental data shown in two figures, according to the retraction notice published2 on 26 September. “The details of the procedure were not specified in the paper and the validity of the background subtraction has subsequently been called into question.”
Through a spokesperson, Dias said that he and his colleagues disagree with the retraction and stand by their results. They will resubmit the paper to Nature with the raw-data plots of the figures. “The retraction request does not question the observed physical superconductivity state of the [carbon-sulfur-hydrogen] material,” says Dias’s statement. He pointed to an arXiv preprint posted4 in 2021 that responds to researchers’ concerns and presented the raw data, and added that three teams had replicated elements of the results.
The retraction follows the publication in Nature of a response to the original paper by physicists Jorge Hirsch of the University of California, San Diego, and Frank Marsiglio at the University of Alberta in Edmonton, Canada. The two had raised multiple questions about the study, in particular regarding the two figures mentioned in the retraction notice. These reported a drop in a feature called magnetic susceptibility when the material was cooled below a critical temperature — which is supposed to be a tell-tale sign of superconductivity. Several other publications had also questioned the claim, as did other physicists who pointed out some of these same issues in interviews with Nature’s news team at the time of the original publication.