ELECTRON RAMAN-SCATTERING IN TL2BA2CUO6+X CRYSTALS

It is inferred from the position of the 2 Delta peak in the electron l ight scattering spectra that in a sample with high T-c approximate to 90 K the ratio 2 Delta/T-c is approximately equal to 6 and 7 for diffe rent polarizations, while in overdoped samples with T-c approximate to 40 and 35 K the 2 Delta peak is observed only in x'y' polarization wi th a substantially lower ratio 2 Delta/T-c approximate to 3.2. With de creasing T-c in Tl2Ba2CuO6+x crystals, a transition occurs from strong to weak coupling; the superconducting gap remains anisotropic at diff erent doping levels. (C) 1996 American Institute of Physics.