Projected entangled pair states study of anisotropic-exchange magnets on triangular lattice

TL;DR

This study uses PEPS to explore the quantum phase diagram of an anisotropic-exchange spin-1/2 model on a triangular lattice, revealing various ordered phases and a Z2 vortex state, but no quantum spin liquid.

Contribution

First application of PEPS to this model, providing detailed quantum phase insights and contrasting with previous DMRG results.

Findings

Identified stripe-ordered, 120°, and multi-Q phases.

Discovered the multi-Q phase as a Z2 vortex state.

Did not find quantum spin liquid phase.

Abstract

The anisotropic-exchange spin-1/2 model on a triangular lattice has been used to describe the rare-earth chalcogenides, which may have exotic ground states. We investigate the quantum phase diagram of the model by using the projected entangled pair state (PEPS) method, and compare it to the classical phase diagram. Besides two stripe-ordered phase, and the 120$^\circ$ state, there is also a multi-\textbf{Q} phase. We identify the multi-\textbf{Q} phase as a $Z_{2}$ vortex state. No quantum spin liquid state is found in the phase diagram, contrary to the previous DMRG calculations.