Pairing Fluctuation Theory of Superconducting Properties in Underdoped to Overdoped Cuprates

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