CUHK team discovers nickel based high-temperature superconductor for the first time in the world

Scientific researchers show new nickel based High-temperature superconductivity materialsProfessor Wang Meng (middle) and team studentsYangcheng Evening News reporter Chen LiangOn July 12, the international academic journal Nature published the scientific achievement led by Professor Wang Meng of Sun Yat-sen University: the first discovery of nickel oxide superconductor at liquid nitrogen temperature. This is a new High-temperature superconductivity system first discovered by Chinese scientists in the world

Scientific researchers show new nickel based High-temperature superconductivity materials

Professor Wang Meng (middle) and team students

Yangcheng Evening News reporter Chen Liang

On July 12, the international academic journal Nature published the scientific achievement led by Professor Wang Meng of Sun Yat-sen University: the first discovery of nickel oxide superconductor at liquid nitrogen temperature. This is a new High-temperature superconductivity system first discovered by Chinese scientists in the world. It is the second unconventional superconductor material found at liquid nitrogen temperature. It is a breakthrough in the field of basic research from 0 to 1. It is expected to promote the understanding of High-temperature superconductivity mechanism and make it possible to design and predict High-temperature superconductivity materials.

Discovery of nickel based high-temperature superconductor

Recently, in the laboratory of Zheshengtang School of Physics on the south campus of Sun Yat-sen University's Guangzhou campus, Professor Wang Meng's team showed us a few centimetres black bar. This is the "new star" discovered this time -- the new High-temperature superconductivity material La_ 3Ni_ 2O_ 7 single crystal samples. This seemingly simple and unadorned material stick embodies the team's years of hard work.

It is reported that superconducting materials have the special properties of absolute zero resistance, complete Diamagnetism and macroscopic quantum tunneling effect, so they have important scientific and application values.

In 1986, scientists first discovered copper oxide superconductors, and then scientists from many countries raised their superconductivity temperature to liquid nitrogen temperature, that is, more than 77 Kelvin. The cheap and easy availability of liquid nitrogen promotes the large-scale application of copper oxide High-temperature superconductivity materials. However, in the past 40 years, the mechanism of High-temperature superconductivity is still one of the most important unsolved problems in physics.

According to Wang Meng, La_ 3Ni_ 2O_ The growth conditions of 7 are extremely harsh, with an average valence state of+2.5, deviating from the stable valence state of Ni by+2, and a narrow range of oxygen pressure. It took the research team more than two years to find out the growth conditions and grow high-quality single crystal samples. Subsequently, the research team will_ 3Ni_ 2O_ 7 Single crystal materials were tested on the high pressure experimental research platform of Sun Yat-sen University, South China University of Technology, the Institute of Physics of the Chinese Academy of Sciences, and the Synchrotron radiation Facility in Beijing. It was quickly determined that they were transformed into superconductors under pressure, and the superconducting transition temperature reached the liquid nitrogen temperature zone, up to 80 Kelvin.

It is expected to crack the mechanism of High-temperature superconductivity

"This discovery of High-temperature superconductivity nickel oxide has a valence of+2.5, which is beyond traditional expectations. Its electronic structure and magnetism are completely different from those of copper oxide. Through comparative research, it will be possible to determine the key factors of High-temperature superconductivity and promote scientists to understand the mechanism of High-temperature superconductivity." Professor Wang Meng introduced, "According to the mechanism, it is expected to design and synthesize more new and easier to apply High-temperature superconductivity materials after crossing with computer, AI technology and other disciplines, so as to achieve more extensive applications."

After being published on the research paper preprint platform during the review stage, this discovery quickly received widespread attention and follow-up research from researchers in the field of superconductivity worldwide. In about a month, more than ten related theoretical and experimental works have been published one after another. The paper has also received high praise from the reviewers of the journal Nature, believing that it is "of outstanding importance", "a groundbreaking discovery", and "widely anticipated in the industry".

This work was led and completed by Professor Wang Meng, School of Physics, Sun Yat-sen University. Sun Hualei, an associate researcher of the School of Physics of Sun Yat-sen University, and Huo Mengwu, a doctoral candidate, are the co first author of the paper, and Wang Meng and Zhang Guangming, a professor of Tsinghua University, are the co corresponding authors of the paper.

"Since 2017, Sun Yat-sen University has built a public research platform of the School of Physics, creating first-class conditions for the team's material growth and characterization experiments." Wang Meng said that the neutron spectrometer built by Sun Yat-sen University will help the team to further study materials and promote the solution of the mechanism.

At present, our superconducting materials need to be achieved at a pressure of 14GPa, which will limit the research on superconducting mechanisms and widespread applications. The research team is currently working on a key issue and hopes to grow nickel oxide superconductors that can achieve liquid nitrogen temperature superconductivity at atmospheric pressure, "said Wang Meng.

Source: Yangcheng Evening News

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