# Vortex-induced topological transition of the bilinear-biquadratic Heisenberg antiferromagnet on the triangular lattice

## TL;DR

This paper investigates a classical Heisenberg antiferromagnet on a triangular lattice with bilinear-biquadratic interactions, revealing a finite-temperature topological phase transition driven by vortices, with implications for experimental materials.

## Contribution

It demonstrates a topological phase transition in the model driven by vortices, a novel insight into the effects of biquadratic interactions on magnetic ordering.

## Key findings

- Finite-temperature topological transition driven by vortices
- Presence of three vortex types depending on biquadratic coupling
- Finite spin correlation length persists below transition

## Abstract

The ordering of the classical Heisenberg antiferromagnet on the triangular lattice with the the bilinear-biquadratic interaction is studied by Monte Carlo simulations. It is shown that the model exhibits a topological phase transition at a finite-temperature driven by topologically stable vortices, while the spin correlation length remains finite even at and below the transition point. The relevant vortices could be of three different types, depending on the value of the biquadratic coupling. Implications to recent experiments on the triangular antiferromagnet NiGa$_2$S$_4$ is discussed.