Anisotropic frustrated Heisenberg model on the honeycomb lattice

TL;DR

This paper explores the complex phase diagram of an anisotropic frustrated Heisenberg model on the honeycomb lattice, revealing a non-classical disordered phase near a highly frustrated point using various computational methods.

Contribution

It combines quantum Monte Carlo, spin-wave, and series expansion techniques to map the phase boundaries and identify a potential quantum disordered phase.

Findings

No classical magnetic order in the highly frustrated region

Absence of long-range valence-bond order in the disordered phase

Spectrum analysis suggests possible topological order

Abstract

We investigate the ground-state phase diagram of an anisotropic Heisenberg model on the honeycomb lattice with competing interactions. We use quantum Monte Carlo simulations, as well as linear spin-wave and Ising series expansions, to determine the phase boundaries of the ordered magnetic phases. We find a region without any classical order in the vicinity of a highly frustrated point. Higher-order correlation functions in this region give no signal for long-range valence-bond order. The low-energy spectrum is derived via exact diagonalization to check for topological order on small-size periodic lattices.