Evidence for a bicritical point in the XXZ Heisenberg antiferromagnet on a simple cubic lattice

TL;DR

This study uses Monte Carlo simulations to identify a bicritical point with Heisenberg symmetry in the phase diagram of the XXZ Heisenberg antiferromagnet on a cubic lattice, clarifying phase transition behaviors.

Contribution

It provides the first clear numerical evidence for a bicritical point with Heisenberg symmetry in this model, comparing results with theoretical predictions.

Findings

Identification of a bicritical point with Heisenberg symmetry

Phase diagram analysis showing meeting of three phases

Comparison with theoretical models

Abstract

The classical Heisenberg antiferromagnet with uniaxial exchange anisotropy, the XXZ model, in a magnetic field on a simple cubic lattice is studied with the help of extensive Monte Carlo simulations. Analyzing, especially, various staggered susceptibilities and Binder cumulants, we present clear evidence for the meeting point of the antiferromagnetic, spin--flop, and paramagnetic phases being a bicritical point with Heisenberg symmetry. Results are compared to previous predictions based on various theoretical approaches.