Disorder-induced freezing of dynamical spin fluctuations in underdoped cuprates

TL;DR

This paper investigates how disorder affects spin fluctuations in underdoped cuprates, showing that disorder can slow down and eventually freeze spin dynamics, leading to static magnetic order and altered spectral properties.

Contribution

It provides a detailed theoretical analysis of disorder effects on spin fluctuations and magnetic order in underdoped cuprates using an unrestricted Hartree-Fock approach.

Findings

Disorder slows down spin fluctuations, leading to spectral weight transfer.

High disorder induces static spin density wave order.

Disordered stripe states exhibit distinct magnetic fluctuation spectra.

Abstract

We study the dynamical spin susceptibility of a correlated d-wave superconductor (dSC) in the presence of disorder, using an unrestricted Hartree-Fock approach. This model provides a concrete realization of the notion that disorder slows down spin fluctuations, which eventually "freeze out". The evolution of disorder-induced spectral weight transfer agrees qualitatively with experimental observations on underdoped cuprate superconductors. For sufficiently large disorder concentrations, static spin density wave (SDW) order is created when droplets of magnetism nucleated by impurities overlap. We also study the disordered stripe state coexisting with a dSC and compare its magnetic fluctuation spectrum to that of the disorder-generated SDW phase.