Top > Research results > The University of Tokyo elucidates a novel superconducting mechanism in rare earth compounds

2017/8/21

The University of Tokyo elucidates a novel superconducting mechanism in rare earth compounds

University Journal Online Editorial Department

　The group of Takashi Takenaka, Assistant Professor Yuta Mizukami, and Professor Takayoshi Shibauchi of the Graduate School of Frontier Sciences, the University of Tokyo will be on August 8th at Kyoto University, Bristol University, UK, Ecole Polytechnique, France, and Max Planck, Germany. In collaboration with researchers at the institute, the superconductor CeCu10Si2 based on the rare earth element Ce (cerium) has realized a superconducting state that cannot be explained by the mechanism of superconductivity based on magnetic fluctuations. Announced that it was revealed.

　Magnetic fluctuations are the most promising candidates for the mechanism of superconductivity that occurs in systems with strong electron-electron interactions.The symmetry of the electronic state in the superconductor is closely related to the superconductivity manifestation mechanism, and the copper oxide high-temperature superconductor, which is a typical example of superconductivity realized in the strongly correlated electron system, has d-wave symmetry. Is known to be.The rare earth superconductor CeCu2Si2 is a prototype and typical example of superconductivity in such strongly correlated electron systems, and was thought to have a d-wave symmetric electronic state similar to cuprate high-temperature superconductors. ..However, recent studies have revealed s-wave symmetry, and the mechanism of superconductivity is drawing attention again.

　This time, as a result of investigating the effect of impurities in the sample on the fragility of superconducting electrons up to 1 millikelvin, which is about 1 / 30 of room temperature, the change in the low energy state peculiar to the magnetic mechanism It became clear that did not appear at all.From this result, superconductivity due to magnetic fluctuation is completely excluded from the superconductivity expression mechanism of CeCu2Si2.

　This result is a discovery that provides definitive evidence for the superconductivity expression mechanism of CeCu2Si2, which has been debated for many years, and aims at a unified understanding of superconductivity expressed in systems with strong electron-electron interactions. It is expected to be an important clue.

Paper Information: [Physical Review Letters] Full-Gap Superconductivity Robust against Disorder in Heavy-fermion CeCu2Si2

Tokyo University

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The University of Tokyo was established in 1877 (Meiji 10) by integrating the Tokyo Kaisei School and the Tokyo Medical School.Since its establishment, it has developed education and research in a unique way in the world as a leading university in Japan and an academic center for the fusion of East and West cultures.As a result, many human resources have been produced in a wide range of fields, and many research achievements […]

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Kyoto University

Foster a free academic style based on the spirit of "self-respect for self-weight" and open up a world of creative learning.

With the motto of self-study, we will continue to maintain a free academic style that is not bound by common sense, and develop human resources who have both creativity and practical ability.We provide an inclusive learning space that allows for diverse and hierarchical choices so that students themselves can choose a solid future through valuable trial and error. […]

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