Pairing Fluctuation Theory of Superconducting Properties in Underdoped to Overdoped Cuprates

TL;DR

This paper presents a theoretical model for the superconducting properties of cuprates across doping levels, emphasizing strong pairing fluctuations and predicting quasi-universal behavior in superfluid density and Josephson current.

Contribution

It introduces a pairing fluctuation theory that explains the doping dependence of $T_c$, $ riangle(0)$, and universal normalized behaviors in superfluid density and Josephson current.

Findings

Calculated $T_c$ and $ riangle(0)$ match experimental trends.

Normalized superfluid density $ ho_s(T)/ ho_s(0)$ shows universal behavior.

Predicted universal behavior of $I_c(T)/I_c(0)$ as a function of $T/T_c$.

Abstract

We propose a theoretical description of the superconducting state of under- to overdoped cuprates, based on the short coherence length of these materials and the associated strong pairing fluctuations. The calculated $T_c$ and the zero temperature excitation gap $\Delta(0)$, as a function of hole concentration $x$, are in semi-quantitative agreement with experiment. Although the ratio $T_c/\Delta(0)$ has a strong $x$ dependence, different from the universal BCS value, and $\Delta(T)$ deviates significantly from the BCS prediction, we obtain, quite remarkably, quasi-universal behavior, for the normalized superfluid density $\rho_s(T)/\rho_s(0)$ and the Josephson critical current $I_c(T)/I_c(0)$, as a function of $T/T_c$. While experiments on $\rho_s(T)$ are consistent with these results, future measurements on $I_c(T)$ are needed to test this prediction.