"Room temperature superconductivity" is popular all over the world again! Physics "holy grail" will start the fourth industrial revolution?

Will we witness the age of superconductivity?

Since the end of July, the "room temperature superconductivity" storm has swept the world. The South Korean team uploaded two papers on arXiv, claiming to have successfully synthesized the worlds first room temperature and atmospheric pressure superconductor - a modified lead apatite crystal structure (LK- 99), shocked the world.

It is reported that LK-99 is a slightly modified hexagonal structure of lead apatite, and a small amount of copper is introduced to enable it to exhibit superconductivity below 127 degrees Celsius. The chemical formula is written as:

Room-temperature superconductors are regarded as one of the "Holy Grails" of modern physics, and the "heavy weight" dropped by the Korean research team once again detonated the physics community.

Some analysts pointed out that the Korean teams LK-99 is "even more incredible" because it not only solves the temperature problem, but also does not even require a "high-voltage assistant." The Tc of 127°C (Note: Tc superconducting transition temperature, that is, the temperature at which a superconductor enters a superconducting state from a normal state) is not only a numerical increase compared with previous studies, but more importantly, the applicable temperature range is greatly improved. broaden.

To put it simply, this sci-fi technology can allow electrons to pass through quickly at room temperature, without resistance and energy consumption, and will subvert the existing power system. The realization of room temperature superconductivity will profoundly change the current energy system, information processing and transmission system, and bring progress in many fields such as medical testing, high-speed transportation and even controllable nuclear fusion.

At present, it is generally believed in the industry that the preparation process of LK-99 seems to be quite simple. The conditions of normal temperature and pressure, and the way of "hand rubbing materials" have made people hopeful in addition to consternation and doubts—in case superconductivity is really So simple, isnt it a huge breakthrough?

Therefore, both those who study materials and those who do not study materials are nervously watching the reproduction process of major laboratories. The results of the first batch of repeated experiments of LK-99 were released: the theory is feasible but no levitation or superconductivity has been reproduced.

At 16:13 on July 31, Beihang researchers submitted a paper on arXiv, saying that the experimental results did not reveal the superconductivity of LK-99. The X-ray diffraction pattern of the LK-99 sample they obtained was consistent with that of the Korean team, but the huge diamagnetism could not be detected, and the magnetic levitation phenomenon was not observed. From the perspective of electrical transport properties, LK-99 is more like a semiconductor; from the perspective of resistivity, LK-99 does not match the zero resistance of a superconductor.

Almost at the same time (17:58 on July 31), Sinead M. Griffin, a researcher at the Lawrence Berkeley National Laboratory (LBNL), submitted a paper titled "Copper-doped lead apatite in the preprint website arXiv". "Origin of correlated isolated flat bands in copper-substituted lead phosphate apatite" paper.

Griffin said that they used the density functional theory (DFT) and GGA+U method to perform calculations, which provided a theoretical basis for the so-called "superconducting materials at room temperature and pressure" by the Korean team recently. She believes that the calculation results show that, LK-99 may have superconducting properties, and has the characteristics of a high-temperature superconductor Fermi level flat band.

On the afternoon of August 1, a domestic Internet blogger published a video saying that the Huazhong University of Science and Technology team successfully synthesized LK-99 "room temperature superconducting crystal" that can be magnetically levitated, and has now passed the verification of the Meissner effect (Note: Meissner effect (Meissner effect) is the repulsion of a superconductor to a magnetic field during the phase transition from a general state to a superconducting state).

But according to him, although this crystal has diamagnetism, it is relatively weak, and there is no so-called "zero resistance", and the overall performance is like a semiconductor curve. He believes that even if LK-99 has a superconducting phase, it is still a trace amount of superconducting impurities, which cannot form a continuous superconducting path.

In the next few days, there will be more results of the recurrence experiment. Researchers from all over the world will work together to verify whether human beings can take off the holy grail of room temperature superconductivity this time and enter a new era.