Topological Order in an Antiferomagnetic Tetratic

TL;DR

This paper investigates a novel melting scenario in two-dimensional antiferromagnets, revealing a tetratic phase characterized by dislocation pairs and bound disclinations, supported by numerical simulations of confined hard spheres.

Contribution

It introduces a new topological melting pathway involving a tetratic phase in antiferromagnets, emphasizing the role of magnetic frustration and dislocation pairing.

Findings

Identification of a tetratic phase separating solid and liquid phases.

Numerical demonstration of the tetratic phase in a system of confined hard spheres.

Observation of antiferromagnetic order within the tetratic phase.

Abstract

We study lattice melting in two dimensional antiferromagnets. We argue that, for strong enough magnetic interactions, single lattice dislocations are prohibitive due to magnetic frustration. This leads to a melting scenario in which a tetratic phase, composed of free dislocation pairs and bound disclinations, separates the solid from the liquid phases. We demonstrate this phase numerically in a system of hard spheres confined between parallel plates, where spins are represented by the the heights of the spheres. We find that, in the tetratic phase, the spins are as antiferromagnetically ordered as allowed by their spatial configuration.