Variational study of the Kitaev-Heisenberg-Gamma model

Abstract

We compute the low-energy excitation spectrum and the dynamical spin structure factor of the Kitaev-Heisenberg-Gamma model through a variational approach based on the exact fractionalized excitations of the pure Kitaev honeycomb model. This novel approach reveals the physical reason for the asymmetric stability of the Kitaev spin liquid phases around the ferromagnetic and antiferromagnetic Kitaev limits. Moreover, we demonstrate that the fractionalized excitations form bound states in specific regions of each Kitaev spin liquid phase and that certain phase transitions induced by Heisenberg and Gamma interactions are driven by the condensation of such a bound state. Remarkably, this bound state appears as a sharp mode in the dynamical spin structure factor, while its condensation patterns at the appropriate phase transitions provide a simple explanation for the magnetically ordered phases surrounding each Kitaev spin liquid phase.

20 pages, 11 figures

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Cited by in corpus (30)

• Beyond Kitaev physics in strong spin-orbit coupled magnets
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• Theory of the Kitaev model in a [111] magnetic field
• Unveiling the S=3/2 Kitaev Honeycomb Spin Liquids
• Unusual excitations and double-peak specific heat in a bond-alternating spin-$1$ $K$-$\Gamma$ chain
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• Spinless fermions in a ${\mathbb{Z}}_2$ gauge theory on the triangular ladder
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• Kinetic Ferromagnetism and Topological Magnons of the Hole-Doped Kitaev Spin Liquid
• Emergent magnetic order in the antiferromagnetic Kitaev model with a [111] field
• Gauge Field Dynamics in Multilayer Kitaev Spin Liquids
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• Electric polarization near vortices in the extended Kitaev model
• Vacancies in generic Kitaev spin liquids
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• Raman spectroscopy of anyons in generic Kitaev spin liquids
• Dynamical Response of the Kitaev Spin Liquid under Third-Nearest-Neighbor Heisenberg Interaction