Bond-Disordered Spin Liquid and the Honeycomb Iridate 
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Knolle, Johannes; Moessner, Roderich; Perkins, Natalia B.

doi:10.1103/physrevlett.122.047202

Cited by 93 publications

(110 citation statements)

References 51 publications

(62 reference statements)

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“…Strong Kitaev-like bond-dependent couplings between effective pseudospins-1/2 have been identified in iridium oxides, such as α-Li 2 IrO 3 and Na 2 IrO 3 , α-RuCl 3 , and other materials [40][41][42][43][44][45][46][47]. In these systems, magnetic ions form the two-dimensional honeycomb lattices stacked along the [111]-direction.…”

Section: Introductionmentioning

confidence: 99%

Magnon damping in the zigzag phase of the Kitaev-Heisenberg- Γ model on a honeycomb lattice

et al. 2020

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We calculate magnon dispersions and damping in the Kitaev-Heisenberg model with an offdiagonal exchange Γ and isotropic third-nearest-neighbor interaction J3 on a honeycomb lattice. This model is relevant to a description of the magnetic properties of iridium oxides α-Li2IrO3 and Na2IrO3, and Ru-based materials such as α-RuCl3. We use an unconventional parametrization of the spin-wave expansion, in which each Holstein-Primakoff boson is represented by two conjugate hermitian operators. This approach gives us an advantage over the conventional one in identifying parameter regimes where calculations can be performed analytically. Focusing on the parameter regime with the zigzag spin pattern in the ground state that is consistent with experiments, we demonstrate that one such region is Γ = K > 0, where K is the Kitaev coupling. Within our approach we are able to obtain explicit analytical expressions for magnon energies and eigenstates and go beyond the standard linear spin-wave theory approximation by calculating magnon damping and demonstrating its role in the dynamical structure factor. We show that the magnon damping effects in both Born and self-consistent approximations are very significant, underscoring the importance of non-linear magnon coupling in interpreting broad features in the neutron-scattering spectra. arXiv:1911.12829v1 [cond-mat.str-el]

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Section: Introductionmentioning

confidence: 99%

Magnon damping in the zigzag phase of the Kitaev-Heisenberg- Γ model on a honeycomb lattice

et al. 2020

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“…To maintain charge neutrality, the charge state of an Ir 4þ ion(s) in their vicinity may change, possibly to Ir 3þ with null spin. If randomly distributed, they might create bond disorder [30] and/or site dilution in the Kitaev Hamiltonian, in addition to the decoration of the Kitaev lattice with additional spin S ¼ 1=2 at the Cu 2þ sites. Curiously, the bulk susceptibility of Cu 2 IrO 3 and Na 2 IrO 3 shares nearly identical Weiss temperature, Θ w ¼ −110 ∼ −123 K [22], whereas Mg 2þ substitution into Na 2 IrO 3 is known to suppress Θ w quickly to almost zero [29].…”

Section: Introductionmentioning

confidence: 99%

Spin Excitations of a Proximate Kitaev Quantum Spin Liquid Realized in Cu2IrO3

et al. 2019

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Magnetic moments arranged at the corners of a honeycomb lattice are predicted to form a novel state of matter, the Kitaev quantum spin liquid, under the influence of frustration effects between bond-dependent Ising interactions. Some layered honeycomb iridates and related materials, such as Na 2 IrO 3 and α-RuCl 3 , are proximate to the Kitaev quantum spin liquid, but bosonic spin-wave excitations associated with undesirable antiferromagnetic long-range order mask the inherent properties of the Kitaev Hamiltonian. Here, we use 63 Cu nuclear quadrupole resonance to uncover the low-energy spin excitations in the nearly ideal honeycomb lattice of effective spin S ¼ 1=2 at the Ir 4þ sites in Cu 2 IrO 3 . We demonstrate that, unlike Na 2 IrO 3 , Ir spin fluctuations exhibit no evidence for critical slowing-down toward magnetic long-range order in zero external magnetic field. Moreover, the low-energy spin excitation spectrum is dominated by a mode that has a large excitation gap comparable to the Ising interactions, a signature expected for Majorana fermions of the Kitaev quantum spin liquid.

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“…As a reaction to this experiment, different proposals are under discussion to explain the results. [38][39][40] One promising approach is to consider disorder in the model's interaction strengths, analyzing the "bond-disordered Kitaev model". 40 In this work, we treat a different problem where we analyze the non-Abelian phase of Kitaev's honeycomb model in the presence of quenched disorder of vortex configurations.…”

Section: Introductionmentioning

confidence: 99%

“…[38][39][40] One promising approach is to consider disorder in the model's interaction strengths, analyzing the "bond-disordered Kitaev model". 40 In this work, we treat a different problem where we analyze the non-Abelian phase of Kitaev's honeycomb model in the presence of quenched disorder of vortex configurations. Since the gauge field and its vortices are static quantities in Kitaev's model, we expect this situation to be well-described by an average over quenched disordered configuration of vortices.…”

Section: Introductionmentioning

confidence: 99%

Dynamical structure factor in the non-Abelian phase of the Kitaev honeycomb model in the presence of quenched disorder

2019

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Kitaev's model of spins interacting on a honeycomb lattice describes a quantum spin-liquid, where an emergent static Z2 gauge field is coupled to Majorana fermions. In the presence of an external magnetic field and for a range of interaction strengths, the system behaves as a gapped, non-Abelian quantum spin-liquid. In this phase, the vortex excitations of the emergent Z2 gauge field have Majorana zero modes bound to them. Motivated by recent experimental progress in measuring and characterizing real materials that could exhibit spin-liquid behavior, we analytically calculate the dynamical spin structure factor in the non-Abelian phase of the Kitaev's honeycomb model. In particular, we treat the case of quenched disorder in the vortex configurations. Our calculations reveal a peak in the low-energy dynamical structure factor that is a signature of the spin-liquid behavior. We map the effective Hamiltonian to that of a chiral p-wave superconductor by using the Jordan-Wigner transformation. Subsequently, we analytically calculate the wave functions of the Majorana zero modes, the energy splitting for finite separation of the vortices and finally, the dynamical structure factor in presence of quenched disorder.

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Bond-Disordered Spin Liquid and the Honeycomb Iridate H3LiIr2O6

Cited by 93 publications

References 51 publications

Magnon damping in the zigzag phase of the Kitaev-Heisenberg- Γ model on a honeycomb lattice

Magnon damping in the zigzag phase of the Kitaev-Heisenberg- Γ model on a honeycomb lattice

Spin Excitations of a Proximate Kitaev Quantum Spin Liquid Realized in Cu2IrO3

Dynamical structure factor in the non-Abelian phase of the Kitaev honeycomb model in the presence of quenched disorder

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