Doping dependence of anisotropic resistivities in the trilayered superconductor Bi2Sr2Ca2Cu3O10+δ -: art. no. 024507

The doping dependence of the thermopower, in-plane resistivity rho(ab)(T), out-of-plane resistivity rho(c)(T), and susceptibility has been systematically measured for high-quality single crystal Bi2Sr2Ca2Cu3O10+delta. We found that the transition temperature T-c and pseudogap formation temperature T-rhoc(*), below which rho(c) shows a typical upturn, do not change from their optimum values in the overdoped region, even though doping actually proceeds. This suggests that, in overdoped region, the bulk T-c is determined by the always underdoped inner planes, which have a large superconducting gap, while the carriers are mostly doped in the outer planes, which have a large phase stiffness.