Universal T-c depression by irradiation defects in underdoped and overdoped cuprates?

We report on a study of the influence of defects introduced in the CuO2 pla nes of cuprates in a wide range of hole dopings x. T-c and electrical resis tivity rho(T) measurements have been performed on electron-irradiated YBa2C u3O7-delta and Tl2Ba2CuO6+x single crystals. A universal scaling between th e decrease in T, and Delta rho(2D) x n, where Delta rho(2D) is the increase of the 2D resistance induced by the defects and n is the carrier concentra tion equal to x, is found for all the samples investigated here. This demon strates that the hole content is the relevant parameter to describe the tra nsport properties all over the phase diagram, in contradiction with a recen t suggestion of a change in the number of carriers from x to 1-x at the opt imal doping. Moreover, the analysis of our data suggests that strong scatte ring persists on the overdoped side.