Second-order phase transition in the Heisenberg model on a triangular lattice with competing interactions

TL;DR

This paper investigates a classical Heisenberg model on a distorted triangular lattice, revealing a second-order phase transition characterized by Z2 vortex dissociation and belonging to the 2D Ising universality class.

Contribution

It demonstrates the simultaneous occurrence of Z2 vortex dissociation and a second-order phase transition in a Heisenberg model with a specific order parameter space.

Findings

Z2 vortex dissociation occurs at the second-order transition point.

The phase transition belongs to the 2D Ising universality class.

The model exhibits Z2 symmetry breaking at the transition.

Abstract

We discover an example where the dissociation of the Z2 vortices occurs at the second-order phase transition point. We investigate the nature of phase transition in a classical Heisenberg model on a distorted triangular lattice with competing interactions. The order parameter space of the model is SO(3)xZ2. The dissociation of the Z2 vortices which comes from SO(3) and a second-order phase transition with Z2 symmetry breaking occur at the same temperature. We also find that the second-order phase transition belongs to the universality class of the two-dimensional Ising model.