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arXiv · 0704.2234

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

Igor F. Herbut
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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.

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Igor F. Herbut. 2007-11-16. Zero-energy states and fragmentation of spin in the easy-plane antiferromagnet on a honeycomb lattice. https://doi.org/10.1103/physrevlett.99.206404

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