Ground-state properties of the 
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 model on a honeycomb lattice

Yamada, Takuto; Suzuki, Takafumi; Suga, Sei–ichiro

doi:10.1103/physrevb.102.024415

Cited by 16 publications

(13 citation statements)

References 33 publications

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“…Likewise, we find NP γ to be adiabatically connected to uncoupled K dimers on bonds with label γ . This is consistent with a recent series expansion on a dimer ansatz[70], which finds the dimerized ansatz to be stable up to almost isotropic couplings.…”

supporting

confidence: 91%

Emergence of nematic paramagnet via quantum order-by-disorder and pseudo-Goldstone modes in Kitaev magnets

Gohlke

Chern

Kim

2020

Phys. Rev. Research

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The appearance of nontrivial phases in Kitaev materials exposed to an external magnetic field has recently been a subject of intensive studies. Here, we elucidate the relation between the field-induced ground states of the classical and quantum spin models proposed for such materials, by using the infinite density matrix renormalization group (iDMRG) and the linear spin wave theory (LSWT). We consider the K model, where and are off-diagonal spin exchanges on top of the dominant Kitaev interaction K. Focusing on the magnetic field along the [111] direction, we explain the origin of the nematic paramagnet, which breaks the lattice-rotational symmetry and exists in an extended window of magnetic field, in the quantum model. This phenomenon can be understood as the effect of quantum order-by-disorder in the frustrated ferromagnet with a continuous manifold of degenerate ground states discovered in the corresponding classical model. We compute the dynamical spin structure factors using a matrix operator based time evolution and compare them with the predictions from LSWT. We, thus, provide predictions for future inelastic neutron scattering experiments on Kitaev materials in an external magnetic field along the [111] direction. In particular, the nematic paramagnet exhibits a characteristic pseudo-Goldstone mode, which results from the lifting of a continuous degeneracy via quantum fluctuations.

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supporting

confidence: 91%

Emergence of nematic paramagnet via quantum order-by-disorder and pseudo-Goldstone modes in Kitaev magnets

Gohlke

Chern

Kim

2020

Phys. Rev. Research

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“…These studies have focused on the isotropic limit, where the exchange interactions are equivalent on each honeycomb lattice bond. In parallel, the effects of exchange anisotropy on the spin frustration have been also explored to find possible QSLs and to understand its connection to KSL [46][47][48][49]. They suggest that the strong zbond region hosts large regions of disordered phases but it is not clear whether they correspond to isolated dimer limit [47,48] or spin liquid states such as the Γ spin liquid (ΓSL) [30,43] or multi-node gapless QSLs [49].…”

Section: Introductionmentioning

confidence: 99%

“…In parallel, the effects of exchange anisotropy on the spin frustration have been also explored to find possible QSLs and to understand its connection to KSL [46][47][48][49]. They suggest that the strong zbond region hosts large regions of disordered phases but it is not clear whether they correspond to isolated dimer limit [47,48] or spin liquid states such as the Γ spin liquid (ΓSL) [30,43] or multi-node gapless QSLs [49]. These numerical studies may also suffer from finite size effects and thus an investigation of the classical KΓ model whereby the bond strength is tuned would offer an insight to the ground states of the anisotropic KΓ quantum model.…”

Section: Introductionmentioning

confidence: 99%

Extent of frustration in the classical Kitaev-$Γ$ model via bond anisotropy

Rayyan,

Luo,

Kee

2021

Preprint

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In the pseudospin-1 2 honeycomb Mott insulators with strong spin-orbit coupling, there are two types of bond-dependent exchange interactions named Kitaev (K) and Γ leading to strong frustration. While the ground state of the Kitaev model is a quantum spin liquid with fractionalized excitations, the ground state of Γ model remains controversial. In particular, the phase diagram of KΓ model with ferromagnetic K and antiferromagnetic Γ interactions has been intensively studied because of its relevance to candidate materials such as α-RuCl3. Numerical studies also included the effects of tuning the bond strengths, i.e, z-bond strength different from the other bonds. However, no clear consensus on the overall phase diagram has been reached yet. Here we study the classical KΓ model with the anisotropic bond strength using Monte Carlo simulations to understand the emerging phases out of competition between two frustrated limits. We also address how the anisotropic bond strength affects the phase diagram and strength of quantum fluctuations. We found various large unit cell phases due to the competing frustrations, and analyzed their intrinsic degeneracy based on the symmetry of the Hamiltonian. Using the linear spin wave theory we showed that the anisotropic bond strength enhances quantum fluctuations in the Γ dominant regime where a small reduced moment is observed. The implications of our findings in relation to the quantum model are also discussed.

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“…Remarkably this gapless critical point supports edge modes that do not hybridise with the bulk modes due to subsystem symmetries. Interestingly in recent studies investigating the role of pseudo-dipolar interactions in both isotropic and anisotropic Kitaev Hamiltonians [47][48][49][50] have found gapless phases [51,52] (often for ferromagnetic Kitaev exchanges). The relevance of these other gapless phases to our work is not immediately clear and needs to be further explored.…”

Section: Introductionmentioning

confidence: 99%