The Korean research team claimed to have synthesized a room temperature superconducting material called LK-99.
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In recent days, papers on room temperature superconductivity have emerged in an endless stream on the pre-printed website arXiv, and the experimental results of LK-99 materials copied by various teams are still being announced.
On August 8th, the research team from Peking University Quantum Materials Science Center submitted a paper on the preprint website arXiv, showing that the LK-99 sample synthesized by their team did not show superconductivity. The team successfully synthesized a polycrystalline ceramic sample similar to LK-99, and its main composition was consistent with the report of the Korean team, and "semi-suspension" was successfully observed in some small pieces.
In addition, by measuring the magnetization of small samples and large samples without the above phenomenon, the research team found that the samples generally contain weak and clear soft ferromagnetic components, which is enough to explain the semi-suspension phenomenon observed in the vertical magnetic field.
Our measurement shows that there is no Messner effect or zero resistance in the sample, so we think that the sample does not show superconductivity. The team said
On the same day, the paper of the National Physics Laboratory of India was also published on the preprint website arXiv. The paper also shows that the samples synthesized by the team have neither diamagnetism nor zero resistance at room temperature, and there is no sign of superconductivity.
CMTC of the Center for Condensed Matter Theory of the University of Maryland forwarded the above two papers on the social platform "X" (formerly Twitter) and tweeted: "With great sadness, we now think that the game is over. LK-99 is not a superconductor, even at room temperature or very low temperature. But inferior materials with very high resistance. In this way, there is no need to argue with the truth, and the data has already spoken. "
The University of Maryland is called College Park. It is a public research university under the University of Maryland system and is known as the "public ivy".
With the release of the experimental results of teams such as Peking University and the University of Maryland, Alex Kaplan, a blogger who has been tracking room temperature superconductivity for a long time, and others think that the results about LK-99 are basically settled, that is, it is not a room temperature superconductor.
However, Zhihu lecturer "Xi Xi Xi", who studies quantum thermodynamics and organic electronics, expressed his views on the paper published by the research team of Peking University.
In his view, the degree of completion of this paper of Peking University is still very low, and many data and pictures are not perfect. It is expected that the original text will be revised or new papers will be published in the future.
In addition, he thinks the weak ferromagnetism mentioned in the paper is far-fetched. "How can there be a ferromagnetic substance with such a small magnetic susceptibility that it is not saturated when added to a 3T magnetic field?"
According to the incomplete statistics of interface journalists, research teams from Beihang University, Huazhong University of Science and Technology, Southeast University, Shanghai University, Qufu Normal University, Taiwan Province University and Peking University have completed the replication experiment. Although the experimental results are different, it is not confirmed that LK-99 is a room temperature superconductor.
Previously, the verification committee of Korea Superconducting Cryogenic Society analyzed the videos and papers of Korea Quantum Energy Research Center, and reached the conclusion that LK-99 could not be proved to be a room temperature superconductor.
At present, the verification Committee has asked the research team of the Korea Quantum Energy Research Center to provide verification samples. However, the research team said that the samples of LK-99 can only be provided after another academic journal has completed the review of this study, and the review process is expected to take two to four weeks.
South Korean superconducting concept stocks plummeted today. SunamCo。 , once rose by 22%, fell by 30%, and fell; Duksung closed down 29%, after rising 24%; Mobiis fell by 26%, after rising by 22%.
China superconducting concept stocks also changed yesterday's gains. Straight flush data shows that over 80% of 19 constituent stocks are green. Among them, State Electricity Inspection (30 1289. SZ) and Bailey Electric (600468. SH), yesterday's daily limit, fell below 9% today.
At the close of August 7th, US Eastern Time, the share price of American Superconductor (AMSC) closed down by 2.52%, continuing the decline before the close of August 8th, with the highest drop exceeding 12%.