Scaling of the strange-metal scattering in unconventional superconductors

• Published in: Nature (London) 2022-02, Vol.602 (7897), p.431-436
• Main Authors: Yuan, Jie, Chen, Qihong, Jiang, Kun, Feng, Zhongpei, Lin, Zefeng, Yu, Heshan, He, Ge, Zhang, Jinsong, Jiang, Xingyu, Zhang, Xu, Shi, Yujun, Zhang, Yanmin, Qin, Mingyang, Cheng, Zhi Gang, Tamura, Nobumichi, Yang, Yi-feng, Xiang, Tao, Hu, Jiangping, Takeuchi, Ichiro, Jin, Kui, Zhao, Zhongxian
• Format: Article
• Language: English
• Subjects: 142/126; 639/301/119/1003; 639/301/119/2795; 639/766/119/1003; 639/766/119/2795; 639/766/119/995; Accuracy; Composition; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; Coordination compounds; Copper; Copper oxides; Doping; Electrical resistivity; electronic properties and materials; Humanities and Social Sciences; multidisciplinary; Organic superconductors; phase transitions and critical phenomena; Scaling laws; Scattering coefficient; Science; Science (multidisciplinary); superconducting properties and materials; Superconductivity; Temperature; Transition temperature; Transition temperatures; Transport properties; Unconventional superconductivity; Unconventional superconductors
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/s41586-021-04305-5

Marked evolution of properties with minute changes in the doping level is a hallmark of the complex chemistry that governs copper oxide superconductivity as manifested in the celebrated superconducting domes and quantum criticality taking place at precise compositions 1 – 4 . The strange-metal state, in which the resistivity varies linearly with temperature, has emerged as a central feature in the normal state of copper oxide superconductors 5 – 9 . The ubiquity of this behaviour signals an intimate link between the scattering mechanism and superconductivity 10 – 12 . However, a clear quantitative picture of the correlation has been lacking. Here we report the observation of precise quantitative scaling laws among the superconducting transition temperature ( T c ), the linear-in- T scattering coefficient ( A 1 ) and the doping level ( x ) in electron-doped copper oxide La 2– x Ce x CuO 4 (LCCO). High-resolution characterization of epitaxial composition-spread films, which encompass the entire overdoped range of LCCO, has enabled us to systematically map its structural and transport properties with unprecedented accuracy and with increments of Δ x  = 0.0015. We have uncovered the relations T c ~ ( x c – x ) 0.5 ~ ( A 1 □ ) 0.5 , where x c is the critical doping in which superconductivity disappears and A 1 □ is the coefficient of the linear resistivity per CuO 2 plane. The striking similarity of the T c versus A 1 □ relation among copper oxides, iron-based and organic superconductors may be an indication of a common mechanism of the strange-metal behaviour and unconventional superconductivity in these systems. Precise quantitative scaling laws are observed between the normalized T -linear coefficient and T c among copper oxides, pnictides and a class of organic superconductors, suggesting a common underlying physics at work in these unconventional superconductors.