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arXiv · 1103.3856

The frustrated Heisenberg antiferromagnet on the honeycomb lattice: A candidate for deconfined quantum criticality

D. J. J. Farnell·R. F. Bishop·P. H. Y. Li·J. Richter·C. E. Campbell
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Abstract

We study the ground-state (gs) phase diagram of the frustrated spin-1/2 $J_{1}$-$J_{2}$-$J_{3}$ antiferromagnet with $J_{2} = J_{3} =κJ_1$ on the honeycomb lattice, using coupled-cluster theory and exact diagonalization methods. We present results for the gs energy, magnetic order parameter, spin-spin correlation function, and plaquette valence-bond crystal (PVBC) susceptibility. We find a Néel antiferromagnetic (AFM) phase for $κ< κ_{c_{1}} \approx 0.47$, a collinear striped AFM phase for $κ> κ_{c_{2}} \approx 0.60$, and a paramagnetic PVBC phase for $κ_{c_{1}} \lesssim κ\lesssim κ_{c_{2}}$. The transition at $κ_{c_{2}}$ appears to be of first-order type, while that at $κ_{c_{1}}$ is continuous. Since the Néel and PVBC phases break different symmetries our results favor the deconfinement scenario for the transition at $κ_{c_{1}}$.

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D. J. J. Farnell, R. F. Bishop, P. H. Y. Li, J. Richter, C. E. Campbell. 2011-03-20. The frustrated Heisenberg antiferromagnet on the honeycomb lattice: A candidate for deconfined quantum criticality. https://doi.org/10.1103/physrevb.84.012403

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