Effects of non-magnetic defects in hole doped cuprates: exploration of the roles of the underlying electronic correlations

Abstract

The effects of non-magnetic iso-valent defects inside the CuO2 plane(s) on superconducting transition temperature, Tc, dc charge transport, and the bulk magnetic susceptibility, \c{hi}(T), were investigated for the YBa2(Cu1-yZny)3O7-d (Zn-YBCO) and La2-xSrxCu1-yZnyO4 (Zn-LSCO) superconductors over a wide range of hole concentrations, p, and Zn contents (y) in the CuO2 plane(s). From the analysis of the \c{hi}(T, y) data, the pseudogap energy scale, {\epsilon}g, was found to be almost independent of the defect content at a given value of p. The Zn induced rate of suppression of Tc, dTc(p)/dy, was found to be strongly p-dependent and showed a systematic variation with hole concentration, except in the vicinity of p ~ 0.125, i.e., near the so-called 1/8th anomaly where the charge and spin stripe orderings are at their strongest in various families of hole doped cuprates. Near p ~ 0.125, the static striped charge ordering is largely believed to dominate the T-p electronic phase diagram. dTc(p)/dy decreased strongly around this composition, i.e., Zn abruptly became less effective in degrading Tc when p ~ 0.125. This observation, together with the facts that (i) Zn suppresses Tc most effectively and (ii) the characteristic pseudogap energy scale remains insensitive to the level of Zn substitution, provide us with important clues regarding the nature and interplay of the underlying electronic correlations present in high-Tc cuprates. We have discussed the possible connections among the stripe ordering, superconducting correlations and the pseudogap phenomenon in details in view of the above findings.