Multicritical points in the three-dimensional XXZ antiferromagnet with single-ion anisotropy

TL;DR

This study uses Monte Carlo simulations to explore the phase diagram of a three-dimensional XXZ antiferromagnet with single-ion anisotropy, revealing multicritical points and the stability of the biconical phase.

Contribution

It provides new insights into the multicritical behavior and phase stability in the 3D XXZ antiferromagnet with single-ion anisotropy, which was not previously well understood.

Findings

Biconical (supersolid) phase becomes thermally unstable below the paramagnetic transition.

Identification of multicritical points where different phases meet.

The phase diagram shows complex multicritical behavior due to anisotropy and field effects.

Abstract

The classical Heisenberg antiferromagnet with uniaxial exchange anisotropy, the XXZ model, and competing planar single-ion anisotropy in a magnetic field on a simple cubic lattice is studied with the help of extensive Monte Carlo simulations. The biconical (supersolid) phase, bordering the antiferromagnetic and spin-flop phases, is found to become thermally unstable well below the onset of the disordered, paramagnetic phase, leading to interesting multicritical points.