Theory of charged impurities in correlated electron materials: Application to muon spectroscopy of high-Tc superconductors

TL;DR

This paper develops a theoretical framework using dynamical mean-field methods to analyze how charged impurities affect correlated electron materials, specifically high-Tc superconductors, with implications for muon spectroscopy interpretations.

Contribution

It introduces a novel approach to quantify impurity effects in correlated systems and assesses their impact on local magnetic properties relevant to muon experiments.

Findings

Correlations significantly modify screening properties.

Muon charge induces observable local spin perturbations.

Implications for interpreting muon-spin-rotation data.

Abstract

Single-site and cluster dynamical mean-field methods are used to estimate the response of a doped Mott insulator to a charged impurity. The effect of correlations on the Thomas-Fermi screening properties is determined. The charge density, the on-site and near-neighbor spin-spin correlations in the vicinity of the impurity are compared to those far from it. The theory is used to address the question of the effect of the density perturbation induced by the muon charge on the local response functions of a high-temperature superconductor. For reasonable values of the background dielectric constant and basic correlation strength, a muon is shown to lead to an observable perturbation of the local spin dynamics, raising questions about the interpretation of muon-spin-rotation experiments in metallic high-temperature superconductors.