Effect of Zn substitution on the suppression of Tc of Y1-xCaxBa2(Cu1-yZny)3O7-delta superconductors: pseudogap and the systematic shift of the optimum hole content

TL;DR

This study investigates how Zn substitution affects the superconducting transition temperature in Y1-xCaxBa2(Cu1-yZny)3O7-delta, revealing a shift in optimal hole content and its relation to the pseudogap phenomenon.

Contribution

It provides new insights into the systematic shift of optimal hole doping and the pseudogap's disappearance with Zn substitution in cuprate superconductors.

Findings

Tc suppression rate varies strongly with hole content p.

Optimal hole content popt shifts to higher values with Zn.

Pseudogap vanishes abruptly at p ≈ 0.185.

Abstract

The effect of Zn substitution on the superconducting transition temperature, Tc, was investigated for the sintered Y1-xCaxBa2(Cu1-yZny)3O7-delta compounds over a wide range of hole concentration per CuO2 plane, p. Ca substitution enabled us to study the deeply overdoped region. p was changed by changing the oxygen deficiency (delta). A strongly p-dependent rate of suppression of Tc with Zn (dTc/dy) was found. From the analysis of the dTc(p)/dy and Tc(p,y) data, we found that the optimum hole content, popt, shifts to higher values with increasing Zn and superconductivity is at its strongest when p = 0.185 +/- 0.005. Various complementary experiments have identified this as the hole content where the pseudogap vanishes quite abruptly. We have discussed the possible relevance to these ideas with our findings.