Zhang Ruozhou, Qin Mingyang, Li Chenyuan, Zhao Zhanyi, Wei Zhongxu, Xu Juan, Jiang Xingyu, Cheng Wenxin, Shi Qiuyan, Wang Xuewei, Yuan Jie, Li Yangmu, Chen Qihong, Xiang Tao, Sachdev Subir, Li Zi-Xiang, Jin Kui, Zhao Zhongxian
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China.
Sci Adv. 2025 Aug 22;11(34):eadu0795. doi: 10.1126/sciadv.adu0795.
Strange-metal behavior has been observed in superconductors ranging from cuprates to pressurized nickelates, but its relationship to unconventional superconductivity remains elusive. Here, we perform operando superfluid density measurements on ion-gated FeSe films. We observe a synchronized evolution of the superconducting condensate and the strange-metal phase with electron doping, from which a linear scaling between zero-temperature superfluid density and strange-metal resistivity coefficient is further established. The scaling also applies to different iron-based and cuprate superconductors despite their distinct electronic structures and pairing symmetries. Such a correlation can be reproduced in a theoretical calculation on the two-dimensional Yukawa-Sachdev-Ye-Kitaev model by considering a cooperative effect of quantum critical fluctuation and disorder. These findings suggest that a common mechanism may govern both the Cooper pair condensation and the normal-state strange metallicity in unconventional superconductors.
从铜酸盐到高压镍酸盐的各类超导体中均观察到了奇异金属行为，但其与非常规超导性的关系仍不明朗。在此，我们对离子门控FeSe薄膜进行了原位超流密度测量。我们观察到超导凝聚态和奇异金属相随电子掺杂的同步演化，据此进一步确立了零温超流密度与奇异金属电阻率系数之间的线性标度关系。尽管不同的铁基和铜酸盐超导体具有不同的电子结构和配对对称性，但该标度关系同样适用。通过考虑量子临界涨落和无序的协同效应，这种相关性能够在二维Yukawa-Sachdev-Ye-Kitaev模型的理论计算中得以重现。这些发现表明，一种共同的机制可能同时支配非常规超导体中的库珀对凝聚和正常态奇异金属性。
