Simplest model to study reentrance in physical systems

TL;DR

This paper investigates the minimal conditions for reentrant phase behavior in physical systems, demonstrating that frustration leads to reentrance in the simplest 2D random bond Ising model across various disorder types.

Contribution

It shows that reentrant behavior is a generic feature of frustrated systems, even in the simplest models, across different disorder distributions.

Findings

Reentrant phase diagrams are observed in the 2D random bond Ising model.

Reentrance occurs at various disorder strengths for both discrete and continuous distributions.

Paramagnetic phases appear at both high and low temperatures, with ferromagnetic phases at intermediate temperatures.

Abstract

We numerically investigate the necessary ingredients for reentrant behavior in the phase diagram of physical systems. Studies on the possibly simplest model that exhibits reentrance, the two-dimensional random bond Ising model, show that reentrant behavior is generic whenever frustration is present in the model. For both discrete and continuous disorder distributions, the phase diagram in the disorder-temperature plane is found to be reentrant, where for some disorder strengths a paramagnetic phase exists at both high and low temperatures, but an ordered ferromagnetic phase exists for intermediate temperatures.