Variational Monte Carlo Study of the 1/9 Magnetization Plateau in Kagome Antiferromagnets

TL;DR

This study uses variational Monte Carlo to explore magnetic phase transitions in a kagome antiferromagnet, revealing a chiral topological spin liquid phase at 1/9 magnetization, consistent with recent experiments.

Contribution

It identifies a chiral $bZ_3$ topological quantum spin liquid phase at 1/9 magnetization in the kagome antiferromagnet, linking theoretical predictions with experimental observations.

Findings

Discovery of a field-induced chiral $bZ_3$ topological spin liquid phase.

Identification of a phase transition from a Dirac spin liquid to the topological phase.

Analysis of physical properties confirming the topological nature of the plateau phase.

Abstract

Motivated by very recent experimental observations of the 1/9 magnetization plateaus in YCu$_3$(OH)$_{6+x}$Br$_{3-x}$ and YCu$_3$(OD)$_{6+x}$Br$_{3-x}$, our study delves into the magnetic field-induced phase transitions in the nearest-neighbor antiferromagnetic Heisenberg model on the kagome lattice using the variational Monte Carlo technique. We uncover a phase transition from a zero-field Dirac spin liquid to a field-induced magnetically disordered phase that exhibits the 1/9 magnetization plateau. Through a comprehensive analysis encompassing the magnetization distribution, spin correlations, chiral order parameter, topological entanglement entropy, ground-state degeneracy, Chern number and excitation spectrum, we pinpoint the phase associated with this magnetization plateau as a chiral $\mathbb{Z}_3$ topological quantum spin liquid and elucidate its diverse physical properties.