Temperature dependence of electrical resistivity of high-Tc cuprates--from pseudogap to overdoped regions

The effects of planar hole concentration, p, and in-plane disorder, Zn (y), on the DC resistivity, ρ(T), of sintered samples of Y1-xCaxBa2(Cu1-yZny)3O7-δ were investigated over a wide doping range by changing both the oxygen deficiency (δ) and Ca content (x). From the ρ(T,p) data we extracted characteristic crossover temperatures on the underdoped and overdoped sides, T* and Tm respectively, above which ρ(T) is linear. We compare our results with a number of other polycrystalline, thin film and single crystal cuprate superconductors and find similar behavior in the p-dependence of T*(p), Tm(p), and the resistivity exponent, m(p), in fits to ρ(T)=ρ0+aTm on the overdoped side. Our findings suggest that the doping level p=0.19±0.01 is special and could possibly be a quantum critical point in the sense that a transition between two different states takes place at zero temperature at this doping (pcrit)