NMR study of high Tc cuprate superconductors with the T' structure

2021 Fiscal Year Final Research Report

• Project/Area Number: 18K03505
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 13030:Magnetism, superconductivity and strongly correlated systems-related
• Research Institution: Chiba University
• Principal Investigator: Fukazawa Hideto 千葉大学, 大学院理学研究院, 准教授 (90361443)
• Co-Investigator(Kenkyū-buntansha): 小堀 洋 千葉大学, 大学院理学研究院, 名誉教授 (10153660) ; 川股 隆行 東北大学, 工学研究科, 助教 (00431601)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: 核磁気共鳴 / 高温超伝導 / 擬ギャップ / 低温物理学

Outline of Final Research Achievements

In T'-PLCCO and T'-LECOF, the phase diagram of the wide-dope region was clarified for the first time from the viewpoint of NMR. The symmetry of the phase diagram with the hole-dope cuprates was found in the optimum and over dope region. In addition, the pseudogap phenomenon was observed for the first time from the viewpoint of NMR.
Similar to the hole-doped cuprates, the symmetry of superconductivity was found to be a spin singlet state with line nodes, that is, d-wave. Furthermore, it was revealed that the antiferromagnetic correlation becomes stronger toward the lower doping region, and that a magnetic quantum phase transition point exists in T'-PLCCO.

Free Research Field

固体物理学

Academic Significance and Societal Importance of the Research Achievements

銅酸化物高温超伝導体の研究の歴史は30年を優に越えた。それにも関わらず、これまでに電子ドープ型においては、NMRの観点から擬ギャップ現象の報告例はなかった。擬ギャップ現象は他の研究手段でも観測されてきたが特性温度は異なっており、これがどのような意味を持つのか、新たな問題を提起出来たと考えている。