A Spin Model for Investigating Chirality

TL;DR

This paper introduces a spin model to study chirality, revealing that ferromagnetic chiral order likely exists for spins 1 and above, but not for spin 1/2, using various analytical and numerical methods.

Contribution

The paper develops a new spin model with ferromagnetic chirality order and analyzes its behavior across different spin magnitudes, expanding understanding of magnetic order parameters.

Findings

Long-ranged chiral order likely exists for spins 1 and higher.

No non-trivial chiral order for spin 1/2.

Uses exact diagonalization, spin-waves, perturbation theory, and mean field analysis.

Abstract

Spin chirality has generated great interest recently both from possible applications to flux phases and intrinsically, as an example of a several-site magnetic order parameter that can be long-ranged even where simpler order parameters are not. Previous work (motivated by the flux phases) has focused on antiferromagnetic chiral order; we construct a model in which the chirality orders ferromagnetically and investigate the model's behavior as a function of spin. Enlisting the aid of exact diagonalization, spin-waves, perturbation theory, and mean fields, we conclude that the model likely has long-ranged chiral order for spins 1 and greater and no non-trivial chiral order for spin 1/2.