Dynamics of fractionalized mean-field theories: consequences for Kitaev materials

Abstract

There have been substantial recent efforts, both experimentally and theoretically, to find a material realization of the Kitaev spin-liquid--the ground state of the exactly solvable Kitaev model on the honeycomb lattice. Candidate materials are now plentiful, but the presence of non-Kitaev terms makes comparison between theory and experiment challenging. We rederive time-dependent Majorana mean-field theory and extend it to include quantum phase information, allowing the direct computation of the experimentally relevant dynamical spin-spin correlator, which reproduces exact results for the unperturbed model. In contrast to previous work, we find that small perturbations do not substantially alter the exact result, implying that $\alpha$-RuCl${}_3$ is perhaps farther from the Kitaev phase than originally thought. Our approach generalizes to any correlator and to any model where Majorana mean-field theory is a valid starting point.

17 pages, 8 figures

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Cited by in corpus (6)

• Quantum liquids of the S=3/2 Kitaev honeycomb and related Kugel-Khomskii models
• Dynamical response theory of interacting Majorana fermions and its application to generic Kitaev quantum spin liquids in a field
• Extracting Nonlinear Dynamical Response Functions from Time Evolution
• Phonon Dynamics in the Chiral Kitaev Spin Liquid
• Real-time control of non-Abelian anyons in Kitaev spin liquid under energy dissipation
• Electric polarization near vortices in the extended Kitaev model