Schwinger-Boson Mean-Field Study of the Anisotropic Kagome Antiferromagnet

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Main Authors: Bakshi, Sankha Subhra, Le, Brandon B., Lee, Seung-Hun, Chern, Gia-Wei
Format: Preprint
Published: 2026
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author Bakshi, Sankha Subhra
Le, Brandon B.
Lee, Seung-Hun
Chern, Gia-Wei
author_facet Bakshi, Sankha Subhra
Le, Brandon B.
Lee, Seung-Hun
Chern, Gia-Wei
contents We investigate the effect of spatial exchange anisotropy on the spin-$1/2$ kagome antiferromagnet using Schwinger-boson mean-field theory. The anisotropy is introduced by strengthening the Heisenberg exchange along one set of nearest-neighbor bonds relative to the other two, and is controlled by a parameter $δ$ that measures the deviation from the isotropic limit. Incorporating the reduced lattice symmetry, we construct the corresponding projective-symmetry-group ansätze and focus on representative $0$- and $π$-flux states connected to the conventional $q=0$ and $\sqrt{3}\times\sqrt{3}$ kagome states. We find that anisotropy predominantly reconstructs the low-energy spinon sector, leading to a strong softening of the lowest spinon branch and a downward shift of the two-spinon continuum. At sufficiently large $δ$, the spinon gap closes at ansatz-dependent values, signaling an instability toward spinon condensation and the onset of magnetic order. From the soft Bogoliubov eigenmodes, we reconstruct the associated incipient spin textures and show that the resulting magnetic orders are intrinsically anisotropic, with suppressed moments on strongly coupled bonds and enhanced moments on more weakly connected sites. These results provide a microscopic picture of how exchange anisotropy drives the transition from kagome spin-liquid states to magnetic order, and offer a framework for interpreting recent experiments on anisotropic kagome materials, particularly titanium-based spin-$1/2$ compounds.
format Preprint
id arxiv_https___arxiv_org_abs_2604_26907
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Schwinger-Boson Mean-Field Study of the Anisotropic Kagome Antiferromagnet
Bakshi, Sankha Subhra
Le, Brandon B.
Lee, Seung-Hun
Chern, Gia-Wei
Strongly Correlated Electrons
We investigate the effect of spatial exchange anisotropy on the spin-$1/2$ kagome antiferromagnet using Schwinger-boson mean-field theory. The anisotropy is introduced by strengthening the Heisenberg exchange along one set of nearest-neighbor bonds relative to the other two, and is controlled by a parameter $δ$ that measures the deviation from the isotropic limit. Incorporating the reduced lattice symmetry, we construct the corresponding projective-symmetry-group ansätze and focus on representative $0$- and $π$-flux states connected to the conventional $q=0$ and $\sqrt{3}\times\sqrt{3}$ kagome states. We find that anisotropy predominantly reconstructs the low-energy spinon sector, leading to a strong softening of the lowest spinon branch and a downward shift of the two-spinon continuum. At sufficiently large $δ$, the spinon gap closes at ansatz-dependent values, signaling an instability toward spinon condensation and the onset of magnetic order. From the soft Bogoliubov eigenmodes, we reconstruct the associated incipient spin textures and show that the resulting magnetic orders are intrinsically anisotropic, with suppressed moments on strongly coupled bonds and enhanced moments on more weakly connected sites. These results provide a microscopic picture of how exchange anisotropy drives the transition from kagome spin-liquid states to magnetic order, and offer a framework for interpreting recent experiments on anisotropic kagome materials, particularly titanium-based spin-$1/2$ compounds.
title Schwinger-Boson Mean-Field Study of the Anisotropic Kagome Antiferromagnet
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2604.26907