Preformed Cooper pairing and the uncondensed normal-state component in phase-fluctuating monolayer cuprate superconductivity

Abstract

We develop a self-consistent microscopic framework beyond mean-field theory for monolayer cuprate superconductivity. It couples fermionic quasiparticles with collective phase dynamics to treat the gap and superfluid stiffness. The phase sector explicitly incorporates both smooth bosonic Nambu-Goldstone phase fluctuations, renormalized by long-range Coulomb interactions, and topological BKT-type vortex-antivortex fluctuations. The required input is the correlated single-particle spectral function, enabling direct interfacing with Hubbard-type models. The theory provides access to key superconducting observables, including T-dependent gap and phase stiffness, gap-closing temperature Tos, and transition temperature Tc, across wide ranges of doping. Using a solvable interaction model as input, our simulations reveal several important features consistent with experimental observations in cuprate superconductors: a d-wave superconducting dome in T−p phase diagram with a shoulderlike anomaly in underdoped regime, a pronounced separation between Tc and Tos signaling preformed Cooper pairing, a finite uncondensed normal component persisting even at T=0, and the onset temperature Ton,vortex of vortex signals, offering a consistent understanding of how strong correlations and phase fluctuations cooperate to shape high-Tc superconductivity.

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