Nature of the Pseudogap in High-Tc Cuprates: Analysis of the Bulk Magnetic Susceptibility of La2−xSrxCu1−yZnyO4

The nature of the pseudogap in the quasiparticle spectral density in high-Tc cuprates is a matter of intense debate. In this study we have investigated the effects of Zn substitution on the uniform (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\boldsymbol{q}=0$\end{document}, where \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\boldsymbol{q}$\end{document} is the wave vector) magnetic susceptibility, χ(T), of La2−xSrxCu1−yZnyO4 sintered samples with different hole concentrations, p(≡x), over a wide range of Zn contents (y). Non-magnetic Zn suppressed Tc most effectively and enhanced χ(T) systematically at low temperatures. We have extracted the characteristic pseudogap energy scale, εg, from the analysis of χ(T) data. Unlike Tc,εg was found to be fairly insensitive to the level of Zn substitution, even when Tc was completely suppressed by Zn. The Zn-induced Curie-like enhancement of the χ(T) was also found to be closely related to the PG energy scale. We discuss the possible implications of these findings in this paper.