Collinear ordering of easy-axis triangular lattice antiferromagnets

TL;DR

This paper investigates how easy-axis single ion anisotropy influences the magnetic ordering of triangular lattice antiferromagnets with larger spins, revealing a novel collinear ordered state that breaks rotational symmetry but preserves translational symmetry.

Contribution

It introduces a new understanding of magnetic ordering driven by easy-axis anisotropy in frustrated triangular lattice antiferromagnets with spins $S \\ge 3/2$, highlighting a symmetry-breaking collinear state.

Findings

Identification of a collinear ordered state induced by easy-axis anisotropy.

The state breaks $\\pi/3$ rotational symmetry.

Translational symmetry remains intact.

Abstract

Antiferromagnetically coupled moments on the frustrated triangular lattice typically order in a coplanar state at low temperature. Here, we demonstrate that the presence of not-very-large easy axis single ion anisotropy leads to an interesting orientationally ordered collinear state in triangular lattice antiferromagnets with moments $S \ge 3/2$. This ordered state breaks the symmetry of $\pi/3$ rotations about a lattice site, while leaving intact the translational symmetry of the lattice.