Cooperon propagator description of high-temperature superconductivity

A phenomenological description of the high-T-c superconductors based on the Cooperon propagator is presented. This model allows one to study the effec ts of local pairing correlations and long-range phase fluctuations on the s ame footing, both above and below T-c. Based on numerical calculations, it is shown that the two types of correlations contribute to the gap/pseudogap in the single-particle excitation spectra. The concourse of these two effe cts can induce low energy states, which should be observable in underdoped materials at very low temperature. (C) 2001 Elsevier Science B.V. All right s reserved.