Scientist who reported room-temperature superconductivity faces more controversy

Ranga Dias, March 2023.
| Photo Credit: Screengrab from University of Rochester video/YouTube

On March 9, the physics journal  Physical Review Letters (PRL) launched an investigation right into a June 2021 paper coauthored, amongst others, by Ranga Dias, following allegations of plagiarism, in the identical week that Dias and others reported in a special journal that that they had found room-temperature superconductivity in a fabric compressed by a couple of thousand atmospheres of stress.

The new declare has thrust Dias and his colleagues again into the highlight, the place they’ve been earlier than for claiming the invention of superconductivity in comparable circumstances, in europium in 2009 and carbonaceous sulphur hydride in 2020.

Now, Dias et al. have reported in  Nature that nitrogen-doped lutetium hydride turns into superconducting at 21º C and underneath 20,000 atmospheres (atm).

The declare has set the condensed-matter physics neighborhood aflutter as a result of the invention of superconductivity at or close to room temperature and ambient stress (i.e. 1 atm) is without doubt one of the discipline’s best pursuits. Researchers have discovered different supplies that superconduct at or close to room temperature however solely once they’re compressed by 100-1,000-times more stress.

Data manipulation and plagiarism

However, despite the fact that the Dias et al. paper has been printed in  Nature, a decent journal, many different physicists have already stated they may maintain off on believing the research information till they will independently confirm it. This is partly due to information availability and Dias’s earlier monitor file – file that now contains the brand new investigation PRL has launched.

After Dias et al. reported in 2009 that europium turns into a superconductor at very low temperature and really excessive stress, not less than one scientist acquired the uncooked information from the experiments from one of many research’s coauthors and located proof of manipulated information. Once the problems got here to gentle, PRL – which had printed the 2009 paper – retracted it in December 2021.

In October 2020, Dias and others reported in  Nature that carbonaceous sulphur hydride (CSH) at round 14º C and a couple of.6 million atm of stress. Soon, unbiased scientists who synthesised the fabric in response to the unique recipe and performed the identical assessments on it that Dias et al. had reached completely different outcomes. The discovering didn’t replicate.

A diamond anvil cell (blue field) was used to supply the excessive stress of two.6 million atm.
| Photo Credit:
J. Adam Fenster

Two days after the europium paper was retracted, Dias and his colleague Ashkan Salamat launched the uncooked information of the CSH paper. There, unbiased scientists rapidly discovered anomalies within the magnetic susceptibility information. When a fabric transitions to a superconducting state, its magnetic susceptibility ought to plummet to zero. This is without doubt one of the checks for superconductivity. The CSH paper was retracted in September 2022.

PRL investigation

Now, James Hamlin, a physicist on the University of Florida, informed  Physics journal that Dias’s 2013 PhD thesis plagiarised from Hamlin’s 2007 thesis. Hamlin has additionally knowledgeable PRL {that a} resistivity plot in Dias’s thesis, for germanium selenide, resembles the identical plot for manganese sulphide in a 2021 PRL paper. These two supplies aren’t speculated to have the identical resistivity plots.

Lilia Boeri, on the Sapienza University of Rome, informed  Physics that the newest discovering reported by Dias et al. is opposite to what physicists know in regards to the behaviour of nitrogen-doped lutetium. Mikhail Eremets, on the Max Planck Institute for Chemistry in Germany, informed  Physics World that unbiased replication of the outcomes might be of “paramount importance”.

Dr. Eremets can be celebrated for his group’s discovery of superconductivity in a metallic hydrogen alloy in 2015, at –70º C Ok and 1.5 million atm. Dias and Isaac Silvera at Harvard University (and Dias’s postdoc mentor) reported in 2017 that that they had made metallic hydrogen (unalloyed) underneath a a lot larger stress of 4.9 million atm. This end result has been acquired unfavourably as nicely.

For now, stories in specialist publications point out that the broader neighborhood’s confidence within the new outcomes stays low. One subject is that the brand new paper favourably cites a disputed approach within the retracted 2020 CSH paper. Another is that, per the  New York Times, Dr. Dias isn’t able to share a exact recipe that others can observe to make the nitrogen-doped lutetium hydride for unbiased assessments as a result of he plans to commercialise the fabric.

But as a result of the brand new end result reportedly requires a lot much less stress to change into superconducting than hydrogen or CSH, physicists count on more labs will capable of independently check the outcomes than earlier than.