Carrier concentrations in Bi2Sr2-zLazCuO6+delta single crystals and their relation to the Hall coefficient and thermopower

We measured the thermopower S and the Hall coefficients R-H of Bi2Sr2-zLazC uO6+delta (BSLCO) single crystals in a wide doping range, in an effort to i dentify the actual hole concentrations per Cu, p, in this system. It is fou nd that the "universal" relation between the room-temperature thermopower a nd T-c does not hold in the BSLCO system. Instead, comparison of the temper ature-dependent R-H data with other cuprate systems is used as a tool to id entify the actual p value. To justify this approach, we compare normalized R-H(T) data of BSLCO, La2-xSrxCuO4 (LSCO), YBa2Cu3Oy, and Tl2Ba2CuO6+delta, and demonstrate that the R-H(T) data of the LSCO system can be used as a t emplate for the estimation of p. The resulting phase diagram of p vs T-c su ggests that T-c is anomalously suppressed in the underdoped samples, becomi ng zero at around p similar or equal to 0.10, while the optimum T-c is achi eved at p similar or equal to 0.16 as expected.