Superconducting Fluctuations in Overdoped Bi2Sr2CaCu2O8+δ

Author(s): He, Y; Chen, SD; Li, ZX; Zhao, D; Song, D; Yoshida, Y; Eisaki, H; Wu, T; Chen, XH; Lu, DH; Meingast, C; Devereaux, TP; Birgeneau, RJ; Hashimoto, M; Lee, DH; Shen, ZX | Abstract: Fluctuating superconductivity—vestigial Cooper pairing in the resistive state of a material—is usually associated with low dimensionality, strong disorder, or low carrier density. Here, we report single-particle spectroscopic, thermodynamic and magnetic evidence for persistent superconducting fluctuations in the heavily hole-doped cuprate superconductor () despite the high carrier density. With a sign-problem-free quantum MontenCarlo calculation, we show how a partially flat band at can help enhance superconducting phase fluctuations. Finally, we discuss the implications of an anisotropic band structure on the phase-coherence-limited superconductivity in overdoped cuprates and other superconductors.