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 heavily hole-doped cuprate superconductor Bi2Sr2CaCu2O8+δ (Tc = 66~K) despite the high carrier density. With a sign-problem free quantum Monte Carlo calculation, we show how a partially flat band at (π,0) 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.
@article{arxiv.2009.10932,
title = {Superconducting fluctuations in overdoped Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$},
author = {Yu He and Su-Di Chen and Zi-Xiang Li and Dan Zhao and Dongjoon Song and Yoshiyuki Yoshida and Hiroshi Eisaki and Tao Wu and Xian-Hui Chen and Dong-Hui Lu and Christoph Meingast and Thomas P. Devereaux and Robert J. Birgeneau and Makoto Hashimoto and Dung-Hai Lee and Zhi-Xun Shen},
journal= {arXiv preprint arXiv:2009.10932},
year = {2021}
}