Spin nematics and magnetization plateau transition in anisotropic Kagome magnets

TL;DR

This paper investigates the phase transitions and ordering phenomena in anisotropic S=1 kagome antiferromagnets, revealing spin-nematic order and a magnetization plateau at 1/3 magnetization through effective model analysis.

Contribution

It introduces an effective S=1/2 XXZ model for large single-ion anisotropy and predicts spin-nematic order and magnetization plateau transitions in kagome magnets.

Findings

Identification of spin-nematic order when D dominates J

Prediction of a magnetization 1/3 plateau state

Mapping of phase diagram with lattice symmetry breaking

Abstract

We study S=1 kagome antiferromagnets with isotropic Heisenberg exchange $J$ and strong easy axis single-ion anisotropy $D$. For $D \gg J$, the low-energy physics can be described by an effective $S=1/2$ $XXZ$ model with antiferromagnetic $J_z \sim J$ and ferromagnetic $J_\perp \sim J^2/D$. Exploiting this connection, we argue that non-trivial ordering into a "spin-nematic" occurs whenever $D$ dominates over $J$, and discuss its experimental signatures. We also study a magnetic field induced transition to a magnetization plateau state at magnetization 1/3 which breaks lattice translation symmetry due to ordering of the $S^z$ and occupies a lobe in the $B/J_z$-$J_z/J_\perp$ phase diagram.