Title: Zn-induced in-gap electronic states in La214 probed by uniform magnetic susceptibility: relevance to the suppression of superconducting Tc,
Abstract: Substitution of isovalent non-magnetic defects, such as Zn, in CuO2 plane
strongly modifies the magnetic properties of strongly electron correlated hole
doped cuprate superconductors. The reason for enhanced uniform magnetic
susceptibility, \c{hi}, in Zn substituted cuprates is debatable. So far, the
observed magnetic behavior has been analyzed mainly in terms of two somewhat
contrasting scenarios, (a) that due to independent localized moments appearing
in the vicinity of Zn arising because of the strong electronic/magnetic
correlations present in the host compound and (b) that due to transfer of
quasiparticle spectral weight and creation of weakly localized low energy
electronic states associated with each Zn atom in place of an in-plane Cu. If
the second scenario is correct, one should expect a direct correspondence
between Zn induced suppression of superconducting transition temperature, Tc,
and the extent of the enhanced magnetic susceptibility at low temperature. In
this case, the low-T enhancement of \c{hi} would be due to weakly localized
quasiparticle states at low energy and these electronic states will be
precluded from taking part in Cooper pairing. We explore this second
possibility by analyzing the \c{hi}(T) data for La2-xSrxCu1-yZnyO4 with
different hole contents, p (= x), and Zn concentrations (y) in this paper.
Results of our analysis support this scenario.