Ising magnets with mobile defects

TL;DR

This paper introduces and analyzes a new 2D Ising model with mobile defects, revealing how defect lines become unstable with temperature increases, supported by simulations and analytical methods.

Contribution

It presents a novel 2D Ising model with mobile defects, combining Monte Carlo simulations and analytical analysis to study defect stripe stability.

Findings

Defect lines meander and become unstable as temperature rises.

The model's robustness is confirmed against weaker interactions.

Analytical and simulation results agree on stripe instability behavior.

Abstract

Motivated by recent experiments on cuprates with low-dimensional magnetic interactions, a new class of two-dimensional Ising models with short-range interactions and mobile defects is introduced and studied. The non-magnetic defects form lines, which, as temperature increases, first meander and then become unstable. Using Monte Carlo simulations and analytical low- and high-temperature considerations, the instability of the defect stripes is monitored for various microscopic and thermodynamic quantities in detail for a minimal model, assuming some of the couplings to be indefinitely strong. The robustness of the findings against weakening the interactions is discussed as well.