On December 13, the Verification Committee of the Korean Society of Superconductivity and Cryogenics issued a statement that "after comprehensively considering the original data and the results of reproduction experiments at home and abroad, it was determinedThere is absolutely no evidence to prove that LK-99 is a superconductor at room temperature and pressure
Yonhap News Agency reported on the 13th (this Wednesday).
Nearly four months have passed since the publication of South Korea's room-temperature superconductivity on July 22. From the world's eye-catching melon-eating carnival when it first appeared, to the Korean research team whose stories were constantly exposed to "infighting", from the reproduction boom of countless professional and non-governmental teams to the long-term inconclusive heat waning after a month, it is simply a ups and downs and dramatic scientific carnival feast.
And now, the South Korean side has finally come to a conclusion that seems to come from the official. Therefore, as soon as the news came out, the topic of "room temperature superconductivity", which had gradually begun to be ignored, once again jumped into the headlines.
Eight universities in South Korea failed to reproduce and still did not get the original samplesThe organization that released *** is a verification committee just established by the Korean Superconducting Low Temperature Society on August 2 this year, and the official website says that the verification committee was specially formed in response to the ongoing controversy surrounding room-temperature superconductors.
One day after its establishment, that is, on August 3, the verification committee submitted a report to the Korean mediaAccording to the Associated Press, the current evidence is not enough to prove the superconductivity of LK-99. However, at that time, the research team refused to provide the original sample to the validation committee on the grounds that ** was still under review, so the conclusion of the validation committee at that time was based on **data and**.
This time, the verification committee said it had asked for samples from the Quantum Energy Research Centre in South Korea, a company founded by Lee Seok-bae, who works on room-temperature superconductivity, but it was still unsuccessful, so it could not be verified by cross-measurement.
However, in ***, the verification committee explained that according to the method proposed by the LK-99 related ** team, 8 Korean studies including Seoul National University have carried out reproduction experiments, and none of them have been able to reproduce superconductivity in a normal or low temperature environment. However, in countless reproduction experiments at home and abroad, there are no cases of resistance 0 and Meissner effect (the repulsion of the magnetic field during the phase transition of an object from a general state to a superconducting state) at the same time. Thus, "most of the results show that LK-99 is a non-conductor with very large resistivity values." ”
The verification committee also added that the topic has a certain effect in arousing social attention and improving the level of understanding of science among the public, but it also leads to unnecessary social controversy due to the misunderstanding of society and ** on the gap between asserting scientific discoveries and their scientific verification, so it is the responsibility of researchers to make initial proof of their scientific findings.
Two ** authors spoke: one admitted, and the other said that he would write again in February next yearBut on December 15 (this Friday), one of the authors of the research team came forward and showed a different attitude towards the conclusion of the validation committee in *** that "there is no evidence that it is a superconductor".
* (The first article released at 7:51 on the day of July 22) For the third work, Kwon Yong-wan, a physics professor from Korea University in South Korea, held a press conference at Korea University on the 15th, sayingIt seems that other authors have made incorrect interpretations, making it difficult to verify. First of all, regarding the phenomenon of LK-99 touching one side and lifting the other side on a magnetic object, Quan Yongwan explained that LK-99 is not a "floating object" like a low-temperature superconductor, on the contrary, because its superconducting antiferromagnetic value is extremely small, and it has molecular antiferromagnetism, so when it floats on a magnetic material, there will only be a part of the contact surface.
This is not to say that there is no Meissner effect, which is one of the characteristics of superconductors and is caused by a 'cooper pair' (a state in which electrons are held together), and LK-99 does form Cooper pairs, but in small quantities. Kwon Yongwan added.
Secondly, regarding the verification committee's claim that the resistivity of LK-99 in the original ** is not zero, but much larger than the resistivity of copper at room temperature (minus 6 ohm centimeters of 10), Kwon Yong-wan said that this is the result shown in Kim Hyun-tae et al.** (the second article published at 10:11 on July 22), and the chart in his ** shows that the measured value is minus 9 square ohm centimeters of 10, which is close to zero resistivity.
For the situation that the reproduction products of other laboratories have not been able to reproduce the consistent characteristics, Quan Yongwan saidThe published ** does not give a complete description of the synthesis process, and if the synthesis process goes wrong, the end result is either a non-conductor or a ferromagnet. This is also what they went through during the experimental phase.
He also added that during the verification process, the verification committee mainly communicated with the Korea Quantum Energy Research Center and did not ask for samples or inquiries from itself.
Finally, Kwon Yongwan said:
By February next year, after a scale-up process to improve the purity of the material, we should be able to measure values similar to previous observations. When the time comes, we will also publish**to further analyze the Meissner effect of LK-99, and if high-purity samples can be obtained by then, it is best to cooperate with domestic and foreign researchers, including academia, to jointly promote superconductivity research.
The scene of the press conference of Korea University on the 15th.
At the same time, Kim Hyun-tae, a physics professor from the College of William and Mary in the United States, responded to Yonhap News Agency by email, saying: ".I think the conclusions of the Society for Superconductivity and Cryogenics (Validation Committee) are correct......LK-99, as defined in patents and dossier**, does not possess superconductivity
In fact, on the 4th day (July 26) after the release of ** at that time, Kim Hyun-tae said in an interview with a new scientist in foreign media that the first ** was uploaded to arxiv without his permission on the premise that there were still "many flaws". Although the Meissner effect can be demonstrated, only one plane is suspended, so he believes that only a part of it actually becomes a superconductor. And he didn't know anything about the statement "opening a new era of human history" in the first article.
After that, Kim Hyun-tae submitted an article to the international journal APL Materials, in which the molecular formula of the material was changed to include sulfur (S). Therefore, Kim Hyun-tae now admits that the conclusion of the verification committee was interpreted by some Korean media as "Kim Hyun-tae believes that the original molecular formula LK-99 is not a superconductor, but the new molecular formula with sulfur added is superconductive at room temperature and atmospheric pressure." ”
In response, a member of the verification committee also responded, saying that foreign researchers have pointed out (that is, the Beijing National Research Center for Condensed Matter Physics of the Institute of Physics of the Chinese Academy of Sciences on August 8) that the part of LK-99 that is considered to be superconductive is actually caused by the phase transition of copper sulfide (Cu2S) impurities. So far, the two most important core personnel in the research team, Lee Seok-bae and Kim Ji-hoon, who named "LK-99" by their initials, have not responded.
Written by: Nandu reporter Yang Bowen.