Zero-energy states and fragmentation of spin in the easy-plane antiferromagnet on a honeycomb lattice

Abstract

The core of the vortex in the Neel order parameter for an easy-plane antiferromagnet on honeycomb lattice is demonstrated to bind two zero-energy states. Remarkably, a single electron occupying this mid-gap band has its spin fragmented between the two sublattices: Whereas it yields a vanishing total magnetization it shows a finite Neel order, orthogonal to the one of the assumed background. The requisite easy-plane anisotropy may be introduced by a magnetic field parallel to the graphene layer, for example. The results are relevant for spin-1/2 fermions on graphene's or optical honeycomb lattice, in the strongly interacting regime.

4 pages; cosmetic changes; published version

References in corpus (6)

• Interactions and phase transitions on graphene's honeycomb lattice
• Electron fractionalization in two-dimensional graphenelike structures
• Theory of integer quantum Hall effect in graphene
• SO(3) symmetry between Neel and ferromagnetic order parameters for graphene in a magnetic field
• Topological degeneracy of non-Abelian states for dummies
• Effective theory of high-temperature superconductors

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• Unconventional superconductivity on honeycomb lattice: the theory of Kekule order parameter
• Near zero modes in condensate phases of the Dirac theory on the honeycomb lattice
• Effect of electron-electron interaction on the Fermi surface topology of doped graphene
• Pseudo-magnetic catalysis of the time-reversal symmetry breaking in graphene
• Zero-energy states bound to a magnetic pi-flux vortex in a two-dimensional topological insulator
• On zero energy states in graphene
• Time reversal, fermion doubling, and the masses of lattice Dirac fermions in three dimensions
• Pairing symmetry and vortex zero-mode for superconducting Dirac fermions
• Midgap spectrum of the fermion-vortex system
• Supersymmetric Runge-Lenz-Pauli vector for Dirac vortex in topological insulators and graphene
• $SO(8)$ unification and the large-N theory of superconductor-insulator transition of two-dimensional Dirac fermions
• Conserved charges of order-parameter textures in Dirac systems
• Zero modes of the generalized fermion-vortex system in magnetic field
• Spin-charge Separation in Nodal Antiferromagnetic Insulator
• Spontaneous breaking of the $\text{SO}(2N)$ symmetry in the Gross-Neveu model
• Zero modes and index theorems for non-Hermitian Dirac fermions
• Zero energy states of Dirac equation in $(2+1)$-dimensional curved spacetime