Two routes to magnetic order by disorder in underdoped cuprates

TL;DR

This paper investigates how disorder induces magnetic order in underdoped cuprates, revealing two distinct magnetic phases depending on impurity strength, with implications for local electronic properties and the density of states.

Contribution

It introduces a detailed analysis of disorder-induced magnetism in cuprates using the Gutzwiller approximation, identifying two magnetic phases based on impurity strength and their effects on electronic structure.

Findings

Disorder creates local antiferromagnetic droplets that merge into quasi-long-range order.

Weak scatterers induce charge reorganization leading to magnetic regions crossing phase boundaries.

Strong scatterers form local static magnetic moments around impurities.

Abstract

We study disorder-induced magnetism within the Gutzwiller approximation applied to the t-J model relevant for cuprate superconductors. In particular, we show how disorder generates magnetic phases by inducing local droplets of antiferromagnetic order which eventually merge, and form a quasi-long range ordered state in the underdoped regime. We identify two distinct disorder-induced magnetic phases of this type depending on the strength of the scatterers. For weak potential scatterers used to model dopant disorder, charge reorganization may push local regions in-between the impurities across the magnetic phase boundary, whereas for strong scatterers used to model substitutional ions, a local static magnetic moment is formed around each impurity. We calculate the density of states and find a remarkably universal low-energy behavior largely independent of both disorder and magnetization. However, the magnetic regions are characterized by larger (reduced) superconducting gap (coherence peaks) and a sub-gap kink in the density of states.