Anomalous scaling corrections and quantum phase diagram of the Heisenberg antiferromagnet on the spatially anisotropic honeycomb lattice

TL;DR

This paper uses large-scale quantum Monte Carlo simulations to map the phase diagram of a spin-1/2 Heisenberg antiferromagnet on an anisotropic honeycomb lattice, revealing complex phase transitions and anomalous scaling behaviors.

Contribution

It provides the first comprehensive phase diagram for the anisotropic honeycomb lattice Heisenberg model, highlighting anomalous scaling corrections at quantum critical points.

Findings

Identified continuous quantum phase transitions between ordered and disordered phases.

Observed large corrections to scaling near phase transition lines.

Discussed non-universality of critical ratios in anisotropic systems.

Abstract

Using large-scale quantum Monte Carlo simulations, we determine the ground state phase diagram of the spin-1/2 antiferromagnetic Heisenberg model on the honeycomb lattice for the most generic case of three varying interaction strengths along the different lattice directions. We identify continuous quantum phase transition lines that separate the long-range ordered antiferromagnetic regime from three distinct quantum-disordered phases, each characterized by dominant dimer-singlet formations. The finite-size behavior along these phase transition lines exhibits anomalously large corrections to scaling, which we relate to similar recent findings in certain dimerized quantum spin systems and to singular one-dimensional limits in the model parameter space. We also comment more generally on the non-universality of critical cumulant ratios in anisotropic systems and attempts to restore universality by varying the aspect ratio.