Pairing Fluctuation Theory of Superconducting Properties in Underdoped to Overdoped Cuprates

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 $\Delta \left(0\right)$, as a function of hole concentration $x$, are in semiquantitative agreement with experiment. Although $T_c/\Delta \left(0\right)$ has a strong non-BCS $x$ dependence, and $\Delta \left(T\right)$ deviates significantly from the BCS prediction, we obtain, remarkably, quasiuniversal behavior for the superfluid density ${\rho }_s\left(T\right)/{\rho }_s\left(0\right)$ and the Josephson critical current $I_c\left(T\right)/I_c\left(0\right)$ as a function of $T/T_c$. Comparison with experiment is addressed.