Cu-spin dynamics in the overdoped regime of La_2-x_Sr_x_Cu_1-y_Zn_y_O_4_ probed by muon spin relaxation

TL;DR

This study uses muon spin relaxation to investigate Cu-spin dynamics in overdoped La_2-x_Sr_x_CuO_4, revealing persistent stripe correlations across the superconducting regime and no quantum critical point at x~0.19.

Contribution

It provides new insights into Cu-spin fluctuations and stripe correlations in overdoped cuprates using muon spin relaxation measurements.

Findings

Zn-induced slowing-down of Cu-spin fluctuations observed

No fast muon spin depolarization at x=0.30 where superconductivity vanishes

Stripe correlations persist throughout the superconducting regime

Abstract

Muon-spin-relaxation measurements have been performed for the partially Zn-substituted La_2-x_Sr_x_Cu_1-y_Zn_y_O_4_ with y=0-0.10 in the overdoped regime up to x=0.30. In the 3 % Zn-substituted samples up to x=0.27, exponential-like depolarization of muon spins has been observed at low temperatures, indicating Zn-induced slowing-down of the Cu-spin fluctuations. The depolarization rate decreases with increasing x and almost no fast depolarization of muon spins has been observed for x=0.30 where superconductivity disappears. The present results suggest that the dynamical stripe correlations exist in the whole superconducting regime of La_2-x_Sr_x_CuO_4_ and that there is no quantum critical point at x~0.19.