Despite the decline, the claim to a room-temperature superconductor is not dead yet

It may be too early to mourn the demise of the claim to room-temperature superconductivity.

On September 26, the magazine temper nature Undo the sheet describing the substance that looked to superconductor at a comfortable temperature of 15°C (SN: 10/14/20). The notice shook many people in the field. But a new experiment conducted just days after the dip supports the global record temperature claim, say an eyewitness and others familiar with the experiment.

Superconductors carry electricity without resistance, which means they are useful for efficient energy transfer. They can save huge amounts of energy that is wasted in traditional metal wires. They are currently used to create strong magnetic fields for medical imaging and particle physics experiments, as well as as components in high-performance circuits and even levitating high-speed trains. But to work, superconducting materials generally must be cooled well below 0 degrees Celsius, and many to temperatures close to absolute zero, or -273 degrees Celsius.

When researchers announced in 2020 that a sample made of hydrogen, sulfur and little carbon Becomes a superconductor at record-breaking temperaturesIt looked like dreams of room-temperature superconductivity were about to come true. One obstacle was that the material would have to be under enormous pressure, about 2.6 million times atmospheric pressure — the pressure roughly found in parts of the Earth’s core. However, this discovery hailed a potential scientific and technological revolution.

In the following two years, controversy erupted over the report. The vortex centers on the way researchers prepare and process data that has shown changes in a magnetic property known as susceptibility. In the end, the editors at temper nature He took the unusual step of withdrawing the paper despite the researchers’ objections. The editors wrote in temper nature in retreat. “Details of the procedure were not specified in the paper after which the validity of the background subtraction has been called into question.”

The new experiment is not a duplicate of the one reported in the attributed paper, but the researchers did replicate a portion of their research that raised red flags in the scientific community.

Ranga Dias, the University of Rochester physicist who led the research on the now-withdrawn paper, led the new measurements at the Advanced Photon Source at Argonne National Laboratory in Lemont, Illinois. “We have been working on this trial for about six months, building and reconfirming the correct methodology,” says Dias. “I would say that the data we got at Argonne is more convincing, and not just comparable,” to the data in temper nature paper.

“The experiment was conducted over two days, September 27 and 28,” says physicist Nilesh Salk of the University of Illinois at Chicago, who was not involved in the original research. Salke’s role at Argonne involved examining a sample of the material in question in X-rays while it was showing magnetic sensitivity associated with high-temperature superconductivity. “We saw the first indication of sensitivity on September 27, consistent with claims made in the retreat temper nature paper.”

This latest shift is unlikely to put an end to the controversy that came with the initial claim, at least in the mind of physicist Jorge Hirsch of the University of California, San Diego. Hirsch has been one of the most vocal critics of the claim to room-temperature superconductivity.

“I didn’t know it would be undone, but I was hoping it would be undone,” says Hirsch, who was not involved in the original or new experiment. He says he asked the authors for raw data from the previous study a month after it was published, but was refused. “The authors said: No, we cannot provide you with the data because our attorneys said it would affect our patent rights.”

interfering from temper natureHirsch finally got the numbers. What he saw disturbed him. Hirsch doubts the possibility of high-temperature superconductivity in these types of hydrogen-based materials in general, but says he objects based on the way the data has been handled.

“There were real issues between the raw data and the published data,” Hirsch says. he thinks that temper natureBacktracking is not enough. “It does not mean that the data has not been properly processed.” With physicist Dirk van der Marel from the University of Geneva Hirsch Dive into data problems In a paper published on September 15 in International Journal of Modern Physics B. “Our analysis mathematically proves that the raw data was not measured in the lab. It was fabricated.”

Dias and his colleagues deny any error in their data or analyzes and are pressing ahead with experiments like the one in Argonne. But this work awaits peer review. So far, temper natureIt reinforces existing doubts about room-temperature superconductivity.

“Ultimately, all of this has to be validated by different groups that get the answer,” Hirsch says.

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