arXiv:1505.07943 · Physical Review B
Magnetization plateaus of an easy-axis kagome antiferromagnet with extended interactions
Xavier Plat, Fabien Alet, Sylvain Capponi, Kiyohito Totsuka
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 ${\mathbb{Z}}_{2}$ 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.