ELECTRONIC RAMAN-SCATTERING IN TL2BA2CUO6- OXYGEN DOPING-EFFECTS(DELTA )

We present electronic Raman scattering measurements of moderately over doped Tl2Ba2CuO6+delta (T-c = 56 K) and compare it with measurements o n optimally and strongly overdoped samples. By taking the pair-breakin g peak in the B-1g scattering component as 2 Delta(0), we found that t he 2 Delta(0)/k(B)T(c) ratio decreases from 8 to 3 with increasing dop ing. Tile intensity of the A,, scattering component decreases by an or der of magnitude in going to the overdoped samples. The behavior of th e low-frequency scattering of the B-1g and B-2g symmetry components fo r T < T-c is ''robust'' for all three dopings. It can be described by the omega(3)- and omega-law, respectively, which is consistent with d- wave symmetry of the superconducting order parameter. Published by Els evier Science B.V.