Incarnation of Majorana Fermions in Kitaev Quantum Spin Lattice

Abstract

Kitaev quantum spin liquid is a topological magnetic quantum state characterized by Majorana fermions of fractionalized spin excitations, which are identical to their own antiparticles. Here, we demonstrate emergence of Majorana fermions thermally fractionalized in the Kitaev honeycomb spin lattice α-RuCl3. The specific heat data unveil the characteristic two-stage release of magnetic entropy involving localized and itinerant Majorana fermions. The inelastic neutron scattering results further corroborate these two distinct fermions by exhibiting quasielastic excitations at low energies around the Brillouin zone center and Y-shaped magnetic continuum at high energies, which are evident for the ferromagnetic Kitaev model. Our results provide an opportunity to build a unified conceptual framework of fractionalized excitations, applicable also for the quantum Hall states, superconductors, and frustrated magnets.

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Cited by in corpus (9)

• Physics of the Kitaev model: fractionalization, dynamical correlations, and material connections
• Breakdown of Magnons in a Strongly Spin-Orbital Coupled Magnet
• Phase Diagram of $\alpha$-RuCl${}_3$ in an in-plane Magnetic Field
• Magnetic thermal conductivity far above the Néel temperatures in the Kitaev-magnet candidate $\alpha$-RuCl${}_3$
• Comprehensive study of the dynamics of a classical Kitaev spin liquid
• Classical and quantum spin dynamics of the honeycomb $\Gamma$ model
• Majorana dynamical mean-field study of spin dynamics at finite temperatures in the honeycomb Kitaev model
• Temperature evolution of spin dynamics in two- and three-dimensional Kitaev models: Influence of fluctuating gauge fluxes
• Detuning the Honeycomb of the α-RuCl3 Kitaev lattice: A case of Cr3+ dopant