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Professor NTU responded to the "falsification of room temperature superconductivity research at the University of Rochester": This repeated experiment is not difficult

author:Modern Express

"Room temperature superconductivity" is hotly discussed again, and the latest progress is here! Previously, the Langa Dias team at the University of Rochester in the United States announced the development of a material that exhibits superconductivity at room temperature and relatively low pressure conditions. Only 8 days after the release, the Nanjing University team published a paper saying that it basically falsified the research results of Langa Dias' team.

Professor NTU responded to the "falsification of room temperature superconductivity research at the University of Rochester": This repeated experiment is not difficult

△ Wen Haihu

The NTU team repeated a similar sample and observed no superconductivity

On March 15, Professor Wen Haihu and his team from the School of Physics at Nanjing University published their repeated experimental results under similar material samples and experimental paths synthesized on the preprint website arXiv. Preprint refers to scientific research papers, scientific and technological reports and other articles that have not been published in official publications, but voluntarily released at academic conferences or through the Internet for the purpose of communicating with peers.

Wen Haihu told Modern Express reporter: "Our results are clear, no superconductivity phenomenon was observed in this sample. "Superconductivity is a matter of presence and absence, there is no third possibility. Superconductivity refers to the fact that some materials have very specific properties at low temperatures: they transmit electric current without any resistance, do not generate heat, and do not waste energy.

In the paper, Wen Haihu's team said: "By increasing the pressure from 1 GPa to 6 GPa, we see that the metal behavior is gradually optimized, but superconductivity is not shown below 10 K. The magnetization temperature dependence shows that it is roughly flat between 100 and 320 K, and the magnetization increases with the magnetic field at 100 K, which does not correspond to superconducting properties at 100 K. Therefore, we conclude that near-room temperature superconductivity is not present in nitrogen-doped lutettate at pressures below 6 GPa. ”

Wen Haihu said: "On March 7, after seeing their [Langa Diaz's] research results, I immediately set about repeating the experiment because I felt that it was too important. It just so happens that we have the required instruments and materials, so the experimental samples come out quickly. Of course, this would not have been possible without the hard work of our colleagues and students. With similar instruments (high-voltage synthesis, electrical and magnetic measurements) and raw material reserves, this repeated experiment is not difficult. ”

Professor NTU responded to the "falsification of room temperature superconductivity research at the University of Rochester": This repeated experiment is not difficult

△ Wen Haihu's team obtained an optical microscope image of a lutetium, nitrogen-hydrogen material

It is understood that the preparation of samples given by Langa Dias' team seems to be a little strange, and the reaction temperature is too low, so Wen Haihu's team combined their own conditions to synthesize in a new way and obtained lutetium, nitrogen, and hydrogen materials. Wen Haihu said: "The main structure of the material is the same, there are three elements, and the composition may be different. The Langa Dias team's article doesn't say exactly how much nitrogen there is, so our samples will have some differences in nitrogen content, but I personally think this may not affect the experimental judgment of superconductivity. ”

Professor NTU responded to the "falsification of room temperature superconductivity research at the University of Rochester": This repeated experiment is not difficult

△The title of the article and its summary published by Wen Haihu's team on arXiv on March 15

Three Chinese teams have repeated the experiment to some degree

In fact, before Wen Haihu's team, the team of researchers Jin Changqing and Cheng Jinguang of the Institute of Physics of the Chinese Academy of Sciences have successively released repeated experiments on lutetium hydrogen compounds on the preprint website arXiv, and so far three Chinese teams have verified this result in different ways, each with its own characteristics, but room temperature superconductivity at atmospheric or low pressure has not been confirmed.

On March 9, Changqing Jin's team from the Institute of Physics of the Chinese Academy of Sciences published their replication work on the preprint website arXiv, which synthesized two lutetium-hydrogen binary compounds that exhibit superconductivity at certain pressures, but the maximum transition temperature was much lower than room temperature, and the required pressure exceeded 100GPa. And the lutetium hydride superconductor material found by Jin Changqing's team has a much greater hydrogen content than the material published by Langa Dias's team.

Cheng Jinguang's team from the Institute of Physics of the Chinese Academy of Sciences paid more attention to the distinctive colors of the samples displayed by Langa Dias' team. On March 12, Cheng Jinguang's team published an article on the preprint website arXiv, saying that the color shift of lutetium hydride at 2.2GPa and 4GPa was observed, similar to the experimental phenomenon published by Diaz's team, but the superconducting phase transition was never observed. It is worth noting that the materials of Cheng Jinguang's team are not doped with nitrogen.

Is there hope for "room-temperature superconductivity"? Wen Haihu told the Modern Express reporter: "I personally think that there is hope, and we need to continue to explore." This direction can continue to be done, not necessarily lutetium, nitrogen-hydrogen materials, but hydrogen-rich materials are likely to reach room temperature superconductivity at low or atmospheric pressure. In addition, along the idea of high-temperature superconductivity research, which is called the 'strong correlation effect' in our circle, the superconducting temperature may be further improved. ”

Modern Express + Reporter Sun Suwan Comprehensive China Science News, Beijing News, "Back to Pu" public account

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