How the ‘room temperature superconductivity’ dream paper became blank – Gigazen

On September 26, 2022, the scientific journal Nature publishedSuperconductivity at room temperature2020 aboutpaperhave withdrawn. If this is achieved, it will evolve into various new technologies such as floating cars, linear actuator cars, small and inexpensive quantum computers, etc., and room temperature superconductivity research was expected to have an impact beyond the industrial revolution. American Association for the Advancement of Science.

‘There is a serious error’: Room-temperature superconductivity study regressed | science | AAAS
https://www.science.org/content/article/something-seriously-wrong-room-temperature-superconductivity-study-retracted

The electrical resistance of a substance becomes zerosuperconductivityAt the time of its discovery, it was a phenomenon that could only be achieved at temperatures close to absolute zero. However, in a research paper in October 2020, a research team led by Ranga Diaz at the University of Rochester, USA, said thathydrideHe reported that he succeeded in raising the temperature at which superconductivity occurs to room temperature by 15 degrees by applying high pressure near the center of the Earth. You can learn more about room temperature superconductivity by reading the following article.

He succeeded in generating ‘superconductivity’ at room temperature, which was considered a low-temperature phenomenon for more than 100 years – Gigazen

by Argonne National Laboratory

However, Nature withdrew Diaz et al.’s paper on Sept. 26. It is considered unusual to withdraw the paper despite the objections of the nine authors. About this, Mr. Diaz said: “We support our research, and its content has been experimentally and theoretically verified.” Ashkan Salamat, a physicist at the University of Nevada and Las Vegas and the other lead author of the paper, notes that the regression does not call into question the drop in electrical resistance that is fundamental to superconductivity,” the editorial board.

Diaz and colleagues’ research on room-temperature superconductivity was pioneered by the search for superconducting hydrides that was first reported in 2015 by Michael Elmette and others from the Max Planck Institute for Science. In the study, Elmette and colleagues compressed a mixture of hydrogen and sulfur. To lower it to minus 70 degrees Celsius.critical temperatureWe found that the electrical resistance drops sharply at -70 degrees far from room temperature, but much hotter than absolute zero.Superconductivity at high temperaturesattracted attention

He succeeded in generating superconductivity in a much higher temperature environment than before – Gigazen

Additionally, in a 2020 study, Diaz and his team crushed the sample with diamonds.diamond anvil cellAs a result of applying a pressure of 267 GPa in the experimental apparatus, we report that the electrical resistance of the hydride decreased sharply.

In the study of superconductivity, it is important to prove not only the low electrical resistance but also another characteristic of superconductors, ‘when the superconductivity state exceeds the critical temperature, the magnetic field is eliminated’. However, it is impractical to measure such phenomena in Diamond anvil cell, so scientists work with hydride more oftenmagnetic susceptibilityIt is said to use the index. However, even in this case, it is necessary to carefully remove magnetic signals from other devices in the room before taking measurements, and they are expressed by the word “something”.

It was this magnetic sensitivity that became a moot point in the undoing of this paper. Diaz and colleagues reported that subtracting the background magnetic signal from the recorded data revealed a magnetic susceptibility signal indicating that superconductivity had occurred, but the paper did not include the raw data. Critics will criticize this point as a “man-made arithmetic result” using assumed values ​​rather than actually measured ones. However, Mr. Salamat says, “In high-pressure physics, it is very difficult to measure background signals, so it is usual to use assumed values. ”

In 2021, Diaz and Salamat explained how they dumped raw sensitivity data and background signals on the arXiv prepress server, after criticizing the missing data.paperannounced. But Brad Ramshaw, a physicist at Cornell University, said: “This paper raises more questions than it answers. The path from raw data to research results has been incredibly murky.”

Reproducibility has also been questioned. Elmette, who reported superconductivity at high temperatures in a 2015 paper, attempted to reproduce the ‘carbon sulfur hydride’ created by Diaz and others in their research, but failed six times. “Diaz and colleagues gave us the basics of the experimental protocol, but they didn’t tell us much about the details, like what kind of carbon they used to make carbonic sulfur hydride,” Elimet said. I didn’t,” he said.

On the other hand, Salamat will restart production of carbonic sulfur hydride in July 2022.paper‘We are opening the door,’ he said, and critics question the study’s independence.

Mr. Diaz, who believes in room-temperature superconductivity research, plans to resubmit a paper showing changes in magnetic susceptibility using only raw data, without removing background signals, back to nature. In addition, Mr. Diaz and Mr. Salamat co-founded a company called Unearthly Materials and are moving towards the commercialization of room-temperature superconductivity.

However, Mr. Elmette said: “I wonder if what Diaz and others claim can be done, because their research is like turning something you hold in your hand into gold. ”, expressed doubts about whether the new superconductors were to Diaz et al. It will stand in the way of scientific verification.