Effects of Zn on superconductivity, stripe order, and pseudogap correlations in YBa2(Cu1−yZny)3O7−δ

Abstract

The effect of Zn substitution in the CuO2 plane on the superconducting transition temperature, Tc, was studied for the YBa2(Cu1−yZny)3O7−δ compounds over a wide range of hole concentration, p, and Zn content (y). Zn induced rate of suppression of Tc, dTc(p)/dy, was found to be strongly p-dependent and showed a monotonic variation with p, except in the region of the 60K plateau where the charge/spin stripe correlations are believed to be at their strongest in Y123. The magnitude of dTc(p)/dy decreased significantly around this composition, implying that Zn suddenly became less effective in degrading Tc. This is somewhat counterintuitive since static stripe ordering itself degrades superconducting order. We have discussed the possible scenarios that can give rise to such an anomalous dTc(p)/dy at the Tc(δ) plateau. We have also looked at the p-dependent characteristic pseudogap energy scale, εg(p), which shows a quasi-linear decrease with increasing p without any noticeable feature in the plateau region. Moreover, there is no appreciable effect of Zn content on the value of εg(p). All these observations are indicative of a complex and possibly competing interplay among the superconducting, pseudogap, and stripe correlations in YBa2(Cu1−yZny)3O7−δ compounds.