Superconductivity in a simple model of the pseudogap state

An analysis is made of characteristics of the superconducting state (s- and d-pairing) using a simple, exactly solvable model of the pseudogap state p roduced by fluctuations of the short-range order (such as antiferromagnetic ) based on a Fermi surface model with "hot" sections. It is shown that the superconducting gap averaged over these fluctuations is nonzero at temperat ures higher than the mean-field superconducting transition temperature T-c over the entire sample. At temperatures T > T-c superconductivity evidently exists in isolated sections ("drops"). Studies are made of the spectral de nsity and the density of states in which superconducting characteristics ex ist in the range T > T-c however, in this sense the temperature T = T-c its elf is no different in any way. These anomalies show qualitative agreement with various experiments using underdoped high-temperature superconducting cuprates. (C) 2000 MAIK "Nauka/Interperiodica".