Comprehensive study of the dynamics of a classical Kitaev spin liquid

Abstract

We study the spin-$S$ Kitaev model in the classical ($S\to \infty$) limit using Monte Carlo simulations combined with semi-classical spin dynamics. We discuss differences and similarities in the dynamical structure factors of the spin-$1/2$ and the classical Kitaev liquids. Interestingly, the low-temperature and low-energy spectrum of the classical model exhibits a finite energy peak, which is the precursor of the one produced by the Majorana modes of the $S=1/2$ model. The classical peak is spectrally narrowed compared to the quantum result and can be explained by magnon excitations within fluctuating one-dimensional manifolds (loops). Hence the difference from the classical limit to the quantum limit can be understood by the fractionalization of magnons propagating in one-dimensional manifolds. Moreover, we show that the momentum space distribution of the low-energy spectral weight of the $S=1/2$ model follows the momentum space distribution of zero modes of the classical model.

12 pages, 8 Figures

References in corpus (16)

• Mott Insulators in the Strong Spin-Orbit Coupling Limit: From Heisenberg to a Quantum Compass and Kitaev Models
• The Kernel Polynomial Method
• On the Origin of Zigzag Magnetic Order in Iridium Oxide Na2IrO3
• Exact results for spin dynamics and fractionization in the Kitaev Model
• Kitaev magnetism in honeycomb RuCl3 with intermediate spin-orbit coupling
• Spin-wave excitations evidencing the Kitaev interaction in single crystalline $\alpha$-RuCl${}_3$
• Vaporization of Kitaev spin liquids
• Honeycomb-lattice Heisenberg-Kitaev model in a magnetic field: Spin canting, metamagnetism, and vortex crystals
• Spin-S Kitaev model: Classical Ground States, Order by Disorder and Exact Correlation Functions
• Magnetic anisotropy in the Kitaev model systems Na2IrO3 and RuCl3
• Phase diagram and spin correlations of the Kitaev-Heisenberg model: Importance of quantum effects
• Order-by-disorder and spin-orbital liquids in a distorted Heisenberg-Kitaev model
• Temperature evolution of spin dynamics in two- and three-dimensional Kitaev models: Influence of fluctuating gauge fluxes
• Classical Heisenberg spins on a hexagonal lattice with Kitaev couplings
• A study of the quantum classical crossover in the spin dynamics of the 2D S=5/2 antiferromagnet Rb2MnF4: neutron scattering, computer simulations, and analytic theories
• Incarnation of Majorana Fermions in Kitaev Quantum Spin Lattice