Field-driven gapless spin liquid in the spin-1 Kitaev honeycomb model

Hickey, Ciarán; Berke, Christoph; Stavropoulos, P. Peter; Kee, Hae‐Young; Trebst, Simon

doi:10.1103/physrevresearch.2.023361

Cited by 49 publications

(33 citation statements)

References 40 publications

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“…On the other hand, at finite temperatures, the above method should be hard to treat both excitations with distinct energy scales. Thus, we use the TPQ state method [30,31], where local quantities are efficiently evaluated without the trace calculations [36][37][38][39][40][41][42]. An important point is that this numerical method takes several energy scales into account on equal footing, and thereby has been successfully used in several systems such as the Heisenberg model on frustrated lattices [30][31][32][43][44][45][46] and the Kitaev models [47][48][49][50][51][52][53].…”

Section: Model and Methodsmentioning

confidence: 99%

Thermally enhanced Majorana-mediated spin transport in the Kitaev model

Taguchi,

Murakami,

Koga

2022

Preprint

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We study how stable the Majorana-mediated spin transport in a quantum spin Kitaev model is against thermal fluctuations. Using the time-dependent thermal pure quantum state method, we examine finite-temperature spin dynamics in the Kitaev model. The model exhibits two characteristic temperatures TL and TH , which correspond to energy scales of the local flux and the itinerant Majorana fermion, respectively. At low temperatures (T TL), an almost flux-free state is realized and the spin excitation propagates in a similar way to that for the ground state. Namely, after the magnetic pulse is introduced at one of the edges, the itinerant Majorana fermions propagate the spin excitations even through the quantum spin liquid state region, and oscillations in the spin moment appear in the other edge with a tiny magnetic field. When T ∼ TL, larger oscillations in the spin moments are induced in the other edge, compared to the results at the ground state. At higher temperatures, excited Z2 fluxes disturb the coherent motion of the itinerant Majorana fermions, which suppresses the spin propagation. Our results demonstrate a crucial role of thermal fluctuations in the Majorana-mediated spin transport.

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Section: Model and Methodsmentioning

confidence: 99%

Thermally enhanced Majorana-mediated spin transport in the Kitaev model

Taguchi,

Murakami,

Koga

2022

Preprint

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“…A similar situation was reported as well for spin-1 Kitaev honeycomb model in candidate materials, such as honeycomb Ni oxides with heavy elements of Bi and Sb, where Kitaev interaction is accompanied by a finite FM Heisenberg interaction. In the zero-field limit, the Kitaev QSL is destabilized when J/K > 0.08 [59]. We thus assume that such interactions are of Heisenberg type,…”

Section: Stability Of Qmbs Against Heisenberg Interactionsmentioning

confidence: 99%

Quantum Many-Body Scars in Spin-1 Kitaev Chains

You,

Zhao,

Ren

et al. 2022

Preprint

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To provide a physical example of quantum scars, we study the many-body scars in the spin-1 Kitaev chain where the so-called PXP Hamiltonian is exactly embedded in the spectra. Regarding the conserved quantities, the Hilbert space is fragmented into disconnected subspaces and we explore the associated constrained dynamics. The continuous revivals of the fidelity and the entanglement entropy when the initial state is prepared in |Z k (k = 2, 3) state illustrate the essential physics of the PXP model. We study the quantum phase transitions in the one-dimensional spin-1 Kitaev-Heisenberg model using the density-matrix renormalization group and Lanczos exact diagonalization methods, and determine the phase diagram. We parametrize the two terms in the Hamiltonian by the angle φ, where the Kitaev term is K ≡ sin(φ) and competes with the Heisenberg J ≡ cos(φ) term. One finds a rich ground state phase diagram as a function of the angle φ. Depending on the ratio K/J ≡ tan(φ), the system either breaks the symmetry to one of distinct symmetry broken phases, or preserves the symmetry in a quantum spin liquid phase with frustrated interactions. We find that the scarred state is stable for perturbations which obey Z2-symmetry, while it becomes unstable against Heisenberg-type perturbations.

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“…Like the famous Haldane chain problem in one dimension, half-odd-integer spin models may have gapless excitations while integer spins may be gapped. Increasingly, many studies have focused on material realization of higher-spin Kitaev models [28,29,31].…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic behavior of modified integer-spin Kitaev models on the honeycomb lattice

et al. 2021

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We study the thermodynamic behavior of modified spin-S Kitaev models introduced by Baskaran, Sen, and Shankar [Phys. Rev. B 78, 115116 (2008)]. These models have the property that for half-odd-integer spins their eigenstates map on to those of spin-1/2 Kitaev models, with well-known highly entangled quantum spin-liquid states and Majorana fermions. For integer spins, the Hamiltonian is made out of commuting local operators. Thus, the eigenstates can be chosen to be completely unentangled between different sites, though with a significant degeneracy for each eigenstate. For half-odd-integer spins, the thermodynamic properties can be related to the spin-1/2 Kitaev models apart from an additional degeneracy. Hence we focus here on the case of integer spins. We use transfer matrix methods, high-temperature expansions, and Monte Carlo simulations to study the thermodynamic properties of ferromagnetic and antiferromagnetic models with spin S = 1 and S = 2. Apart from large residual entropies, which all the models have, we find that they can have a variety of different behaviors. Transfer matrix calculations show that for the different models, the correlation lengths can be finite as T → 0, become critical as T → 0, or diverge exponentially as T → 0. The Z 2 flux variable associated with each hexagonal plaquette saturates at the value +1 as T → 0 in all models except the S = 1 antiferromagnet where the mean flux remains zero as T → 0. We provide qualitative explanations for these results.

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Field-driven gapless spin liquid in the spin-1 Kitaev honeycomb model

Cited by 49 publications

References 40 publications

Thermally enhanced Majorana-mediated spin transport in the Kitaev model

Thermally enhanced Majorana-mediated spin transport in the Kitaev model

Quantum Many-Body Scars in Spin-1 Kitaev Chains

Thermodynamic behavior of modified integer-spin Kitaev models on the honeycomb lattice

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