Instability of the ferromagnetic phase under random fields in an Ising spin glass with correlated disorder

TL;DR

This paper demonstrates that correlated disorder in an Ising spin glass destabilizes the ferromagnetic phase under random fields across all dimensions, highlighting the significant influence of spatial disorder correlations.

Contribution

It reveals that correlated disorder causes ferromagnetic phase instability under random fields, contrasting with uncorrelated models, and links this instability to magnetic and disorder chaos.

Findings

Ferromagnetic phase becomes unstable under random fields with correlated disorder.

Instability is connected to magnetic and disorder chaos.

Correlated disorder preserves ferromagnetism only if the spin glass phase exists under a magnetic field.

Abstract

It is well established that the ferromagnetic phase remains stable under random magnetic fields in three and higher dimensions for the ferromagnetic Ising model and the Edwards-Anderson model of spin glasses without correlation in the disorder variables. In this study, we investigate an Ising spin glass with correlated disorder and demonstrate that the ferromagnetic phase becomes unstable under random fields in any dimension, provided that magnetic field chaos exists in the Edwards-Anderson model on the same lattice. Additionally, we show that this instability can also be attributed to disorder (bond) chaos. We further argue that the model with correlated disorder remains in the ferromagnetic phase even in the presence of symmetry-breaking fields, as long as the Edwards-Anderson model on the same lattice exhibits a spin glass phase under a magnetic field. These results underscore the profound impact of spatial correlations in the disorder.