SUPERCONDUCTING FLUCTUATION AND PSEUDOGAP PHENOMENA IN HIGH-T-C CUPRATES

A number of experiments indicate a sudden decrease in the quasi-partic le density of states as the temperature decreases through T, which is usually far above T-c, the superconducting transition temperature, He re we propose this rather sudden change is due to the superconducting fluctuation. When a parameter x(phi), which characterizes the supercon ducting fluctuation, increases beyond, say 0.25, the effect becomes qu ite visible with decreasing temperature. This point is given roughly T similar or equal to E(F)ln(T*/T-c) where E-F is the Fermi energy (si milar to 200 - 100 K) in the underdoped region.