[Core Story] Taking stock of the academic circle to verify the room temperature superconducting LK-99, is it a rollover or a new era？

　　Collecting micro-grid news, the "room temperature superconductivity" with its own traffic is coming again. On July 22nd, the related research team of Korea Quantum Energy Research Center Company published two similar papers on the preprint website, claiming that a copper-doped lead apatite material named LK-99 has the superconducting ability of "room temperature+atmospheric pressure", which is the first superconducting material at room temperature and atmospheric pressure in the world.

　　Room temperature superconductivity, that is, superconductivity at room temperature. Previous superconducting materials need to enter the superconducting state at a low temperature. The South Korean research team claims that the critical temperature of the synthesized room temperature and atmospheric pressure superconductor is 127℃. If this result is verified, many fields such as energy, transportation and quantum computing are expected to usher in subversive changes.

　　Due to the detailed synthesis steps given in the above paper, many academics said that the steps are not complicated and can be reproduced. And such a way of "rubbing materials by hand" has sparked heated discussions on major social platforms: Is it a new era to open the fourth industrial revolution? Or hit the face and roll over?

　　Since the beginning of this year, there has been a lot of news in the field of superconductivity. First, Dias in the United States made a big news in March, then South Korean scientists synthesized 400K superconducting materials, and then Chinese scientists discovered nickel oxide superconductors in the liquid nitrogen temperature zone .......................................................................................................

　　Realize "room temperature superconductivity"? To be further verified.

　　On July 29th, Liu Peitao, a researcher at the Institute of Metals, Chinese Academy of Sciences, submitted a paper entitled "First-principles Study on the Electronic Structure of Pb10-xCux(PO4)6O (x=0, 1)" on the preprinted website.

　　"The energy band structure of LK-99 near Fermi level has the characteristics of semi-filled flat band and fully occupied flat band. These two flat bands come not only from the 2p orbital of the oxygen atom occupied by 1/4, but also from the hybridization between the 3d orbital of Cu and the 2p orbital of its nearest neighbor oxygen atom. " The research team observed four Van Hoff singularities on the above two flat belts. "This shows that electrons are unstable to structural distortion at low temperatures."

　　On 31st, Professor Liu Zhiqi from School of Materials Science and Engineering, Beihang University submitted a paper entitled "Semiconductor Transmission in Pb10-xCux(PO4)6O Sintered from Pb2SO5 and Cu3P" on the preprinted website. They synthesized LK-99 according to the method announced by the Korean team, but they didn't find it superconducting. "Instead, they found the characteristics similar to semiconductors."

　　On the same day, Sinead M. Griffin, a researcher at Lawrence Berkeley National Laboratory (LBNL) in the United States, submitted a paper entitled "The Origin of Related Isolated Flat Zones in Copper Doped Lead Apatite" on the preprinted website arXiv. She believes that the calculation results show that LK-99 may have superconducting properties.

　　More interestingly, in addition to the Korean research team, the United States also exposed new research results of room temperature superconductors.

　　Image source: Taj Quantum

　　On the 31st, American Taj Quantum Company announced the discovery of a room temperature superconducting material, which is a graphene foam material. Taj Quantum said: "This unique Type II superconductor (patent number: 17249094) can work in a wide temperature range, including temperatures far above room temperature, from about-100 F (-73 C) to about 302°F (150°C), which is an unusual feature in the field of superconductivity." But more experimental data have not been published.

　　On August 1st, bilibili UP owner "Sekinoyamaguchi Male Technician" announced that they have synthesized LK-99 crystal which can be magnetically levitated, and the suspension angle of this crystal is larger than that of the sample obtained CEO Sukbae Lee, CEO of Korean Quantum Energy Research Center, and it is expected to realize the real contactless superconducting magnetic levitation. It is reported that the UP is from Huazhong University of Science and Technology, and its team is led by Chang Haixin, a professor at Huazhong University of Science and Technology, and its members are postdoctoral Wu Hao and doctoral student Yang Li.

　　The shell also pointed out that the successful reproduction of magnetic levitation can only prove that LK-99 has diamagnetism, that is, there is repulsion between LK-99 and magnets, but it cannot prove that LK-99 has the characteristics of normal temperature superconductivity claimed by the Korean team. The so-called complete diamagnetism is only a necessary condition for superconductors, but not a sufficient condition. To verify whether LK-99 is a room temperature superconductor, the key is to measure whether the sample shows zero resistance characteristics. Unfortunately, due to the limitation of sample conditions, the sample that reproduces magnetic levitation can not be used to measure resistance. The laboratory of Huazhong University of Science and Technology has been preparing a new batch of samples, hoping to further measure the resistance characteristics of LK-99.

　　Illusion and Hope Qi Fei, let the bullet fly for a while.

　　On July 28th, Wen Haihu, a professor at the School of Physics of Nanjing University, said in an interview with 澎湃 Technology that "most people are not superconducting" and "we carefully analyzed their data, and three aspects-resistance, magnetization and so-called magnetic levitation-are not enough to show that it is a superconducting phenomenon (material)" and "we judge that (its so-called superconductivity) is probably an illusion".

　　And is there really a material that can enter the superconducting state at normal temperature and pressure? Wen Haihu said that it does not rule out the existence. But this is a very ambitious goal. As for whether we can see it in our lifetime, I don't know.

　　Guo Ming, an analyst of Tianfeng International Securities, posted on the social platform on August 2: "The commercialization of HTS at room temperature and pressure has no visibility, but if it can be commercialized smoothly in the future, it will have a subversive impact on the product design in the field of calculators and consumer electronics. The technology and material innovation of calculators and consumer electronics are all aimed at achieving the requirements of high-speed operation, high-frequency and high-speed transmission, miniaturization, etc., and the characteristics of superconducting state (loss of resistance) will subvert the existing product design and material/technology adoption, such as: no need for cooling system, replacement of optical fiber/high-order CCL, lowering the threshold of advanced process, etc., so that even mobile devices as small as iPhone can have the computing power comparable to quantum computers. "

　　The final trend of "room temperature superconductivity" of Korean scientific research team is still in the dark, which needs further experimental verification by more scientific research institutes. However, it reminds Jiwei.com of a past event: on March 7th this year, Ranga Dias of the University of Rochester in the United States announced at the american physical society conference that a lutetium nitrogen-hydrogen material developed by her could realize room-temperature superconductivity at nearly 10,000 atmospheres (1 GPa).

　　Only eight days later, Wen Haihu's team submitted a 16-page research paper on the preprint website, including nine authors, entitled "Nitrogen-doped Lutetium Hydroxide (LuH2±xNy) does not have superconductivity in the near environment" and "slapping" the conclusion of Dias research. The paper concludes: "The experiment clearly shows that there is no superconductivity in Lutetium nitrogen hydrogen material LuH2±xNy from the ambient pressure to 6.3 GPa and the temperature as low as 10K (about -263 degrees Celsius)."

　　Guotai Junan pointed out that superconducting materials have significant performance advantages, but room temperature superconductivity is still in the laboratory research and development stage. Superconductors can exhibit zero resistance characteristics below special temperature, and do not produce Joule heat, so they can be applied to large-scale integrated circuits. Superconductors can avoid potential drop and energy attenuation, can carry large current without loss, and can solve the problem of long-distance power transmission; Superconductors can significantly improve the high-speed performance of maglev trains because of their complete diamagnetism. The breakthrough of superconducting materials is expected to promote the progress of controlled nuclear fusion technology. At present, the preparation of superconductors requires extremely high ambient temperature and pressure, and the research and development of room-temperature superconductors is theoretically feasible but difficult to operate. From other experiments conducted by Korean research team and Net Transmission, it may only verify the diamagnetic characteristics of materials, but not fully verify the zero-resistance characteristics of materials. Therefore, we should maintain a rational and objective attitude towards the research and commercialization of room-temperature superconductors and closely follow the subsequent experimental verification.

　　I'm afraid this "bullet" that shoots into the future will fly for a while.