Magnetization plateaus of an easy-axis Kagom\'e antiferromagnet with extended interactions

TL;DR

This study explores magnetization plateaus in an extended anisotropic Kagome lattice spin model, revealing crystal and spin liquid phases through simulations and effective models, advancing understanding of frustrated magnetism.

Contribution

It introduces a detailed analysis of magnetization plateaus in an extended Kagome XXZ model, identifying novel crystalline and topological phases using effective models and large-scale simulations.

Findings

Magnetization plateaus at m=1/6 and 1/3 are observed.

Stripe order and Z2 spin liquid phases are identified.

Effective models reveal symmetry-breaking and topological phases.

Abstract

We investigate the properties in finite magnetic field of an extended anisotropic XXZ spin-1/2 model on the Kagome lattice, originally introduced by Balents, Fisher, and Girvin [Phys. Rev. B, 65, 224412 (2002)]. The magnetization curve displays plateaus at magnetization m=1/6 and 1/3 when the anisotropy is large. Using low-energy effective constrained models (quantum loop and quantum dimer models), we discuss the nature of the plateau phases, found to be crystals that break discrete rotation and/or translation symmetries. Large-scale quantum Monte-Carlo simulations were carried out in particular for the m=1/6 plateau. We first map out the phase diagram of the effective quantum loop model with an additional loop-loop interaction to find stripe order around the point relevant for the original model as well as a topological Z2 spin liquid. The existence of a stripe crystalline phase is further evidenced by measuring both standard structure factor and entanglement entropy of the original microscopic model.