Doping Dependence of Anisotropic Resistivities in Trilayered Superconductor Bi2Sr2Ca2Cu3O10+delta (Bi-2223)

TL;DR

This study investigates how doping levels affect anisotropic resistivities and related properties in a trilayered high-temperature superconductor, revealing that the bulk transition temperature remains constant in the overdoped region due to inner plane underdoping.

Contribution

It provides new insights into the doping dependence of resistivities and the role of inner and outer planes in trilayered cuprate superconductors.

Findings

Transition temperature Tc remains unchanged in overdoped region.

Pseudogap temperature T_rho_c* is unaffected by doping in the overdoped region.

Bulk Tc is governed by underdoped inner planes despite doping in outer planes.

Abstract

The doping dependence of the themopower, 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 Tc and pseudogap formation temperature T_rho_c*, 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 plane, which have a large superconducting gap, while the carriers are mostly doped in the outer planes, which have a large phase stiffness.