Crossovers and phase coherence in cuprate superconductors

High temperature superconductivity is a property of doped antiferromagnetic insulators. The electronic structure is inhomogeneous on short length and rime scales, and, as the temperature decreases, it evolves via two crossovers, before long range superconducting order is achieved. Except possibly for overdoped materials, pairing and phase coherence occur at different temperatures, and phase fluctuations determine both T-c and the temperature dependence of the superfluid density for a wide range of doping. A mechanism for obtaining a high pairing scale in a short coherence length material with a strong poorly-screened Coulomb interaction is described. (C) 1998 Elsevier Science Ltd. All rights reserved.