Theory of partial quantum disorder in the stuffed honeycomb Heisenberg antiferromagnet

Abstract

Recent numerical results [Gonzalez $\text{et al.}$, Phys. Rev. Lett. $\text{122}$, 017201 (2019); Shimada $\text{et al.}$, J. Phys. Conf. Ser. $\text{969}$, 012126 (2018)] point to the existence of a partial-disorder ground state for a spin-1/2 antiferromagnet on the stuffed honeycomb lattice, with 2/3 of the local moments ordering in an antiferromagnetic Néel pattern, while the remaining 1/3 of the sites display short-range correlations only, akin to a quantum spin liquid. We derive an effective model for this disordered subsystem, by integrating out fluctuations of the ordered local moments, which yield couplings in a formal $1/S$ expansion, with $S$ being the spin amplitude. The result is an effective triangular-lattice XXZ model, with planar ferromagnetic order for large $S$ and a stripe-ordered Ising ground state for small $S$, the latter being the result of frustrated Ising interactions. Within the semiclassical analysis, the transition point between the two orders is located at $S_c=0.646$, being very close to the relevant case $S=1/2$. Near $S=S_c$ quantum fluctuations tend to destabilize magnetic order. We conjecture that this applies to $S=1/2$, thus explaining the observed partial-disorder state.

13 pages, 7 figures; expanded on experimental signatures, v2 as published

References in corpus (11)

• Pyrochlore Photons: The U(1) Spin Liquid in a S=1/2 Three-Dimensional Frustrated Magnet
• Weak magnetism and non-Fermi liquids near heavy-fermion critical points
• Fractionalized Fermi liquids
• Spin liquid phase of the $S=\frac{1}{2}$ $J_1-J_2$ Heisenberg model on the triangular lattice
• Topography of Spin Liquids on a Triangular Lattice
• Possible valence-bond condensation in the frustrated cluster magnet LiZn2Mo3O8
• Frustration and quantum criticality
• Emergent orbitals in the cluster Mott insulator on a breathing Kagome lattice
• Partial disorder in an Ising-spin Kondo lattice model on a triangular lattice
• Correlated partial disorder in a weakly frustrated quantum antiferromagnet
• Classical phase diagram of the stuffed honeycomb lattice

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