Extended symmetric quantum phase in a honeycomb Heisenberg model with sublattice-selective interactions
Abstract
Motivated by two-dimensional bilayer systems we numerically study an anti-ferromagnetic spin-1/2 Heisenberg model on the honeycomb lattice with a nearest-neighbour exchange coupling J1, and a next-nearest-neighbour exchange coupling J2' for the B sublattice sites only. Using infinite Projected Entangled-Pair States (iPEPS), variational uniform matrix-product states on cylinders, and exact diagonalization, we find an extended symmetric regime 0.4≲ J'2/J1≲0.6, in which local observables show no magnetic, valence-bond, or chiral spin order. At J'2/J1=0.5, the PEPS correlation length grows systematically with bond dimension, and an inverse-correlation-length extrapolation favors a vanishing limit. We also find that various observables scale algebraically with the finite bond-dimension-induced correlation length, which points to a gapless spin liquid ground state. We propose a ℤ2 Dirac spin liquid parton state, with Dirac points that are protected by translation, time-reversal and three-fold rotation symmetry, as a promising candidate state to explain the numerical results. We also discuss the possibility that the symmetric ground state is a featureless, short-range entangled state with a small gap.
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BibTeX
@misc{hu2026extended,
title = {{Extended symmetric quantum phase in a honeycomb Heisenberg model with sublattice-selective interactions}},
author = {Nai Chao Hu and Xing-Yu Zhang and Yuchi He and Nick Bultinck},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.25243},
eprint = {2609.25243},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.25243},
}
RIS
TY - UNPB
TI - Extended symmetric quantum phase in a honeycomb Heisenberg model with sublattice-selective interactions
AU - Nai Chao Hu
AU - Xing-Yu Zhang
AU - Yuchi He
AU - Nick Bultinck
PY - 2026
DA - 2026/09/21
PB - arXiv
DO - 10.48550/arxiv.2609.25243
UR - https://arxiv.org/abs/2609.25243
AB - Motivated by two-dimensional bilayer systems we numerically study an anti-ferromagnetic spin-1/2 Heisenberg model on the honeycomb lattice with a nearest-neighbour exchange coupling J_1, and a next-nearest-neighbour exchange coupling J_2' for the B sublattice sites only. Using infinite Projected Entangled-Pair States (iPEPS), variational uniform matrix-product states on cylinders, and exact diagonalization, we find an extended symmetric regime 0.4≲ J'_2/J_1≲0.6, in which local observables show no magnetic, valence-bond, or chiral spin order. At J'_2/J_1=0.5, the PEPS correlation length grows systematically with bond dimension, and an inverse-correlation-length extrapolation favors a vanishing limit. We also find that various observables scale algebraically with the finite bond-dimension-induced correlation length, which points to a gapless spin liquid ground state. We propose a ℤ_2 Dirac spin liquid parton state, with Dirac points that are protected by translation, time-reversal and three-fold rotation symmetry, as a promising candidate state to explain the numerical results. We also discuss the possibility that the symmetric ground state is a featureless, short-range entangled state with a small gap.
ER -