Charge transport of Bi₂₋ₓPbₓSr₂ErCu₂O₈ single crystals near the insulator-superconductor transition

الأصل · EN

We prepared a set of Pb-substituted Bi₂₋ₓPbₓSr₂ErCu₂O₈ single crystals. The resistivity and the in-plane thermopower decrease with increasing x from 0 to 0.8, which indicates that the Pb substitution supplies holes in the CuO₂ plane. For x=0.8, a tiny resistivity drop (a trace of superconductivity) is seen near 70 K, suggesting that the doping level is close to the critical concentration. The c-axis dielectric constant also systematically changes with x, and suggests that the charge inhomogeneity is suppressed by the Pb substitution.