Indirect coupling between localized magnetic moments in triangular graphene nanoflakes
arXiv:1304.2162 · doi:10.1016/j.physe.2013.03.017
Abstract
The indirect, charge-carrier mediated coupling between localized magnetic moments is studied for graphene nanoflakes of triangular shape and zig-zag edge. The characteristic feature of such nanoflakes is the presence of a shell of zero-energy states in the electronic spectrum. The tight-binding Hamiltonian supplemented with a Hubbard term is used for electronic structure calculations. The indirect RKKY (Ruderman-Kittel-Kasuya-Yosida) coupling energy is derived from the total electronic energy of the system in a non-perturbative way. The attention is focused on the on-site and plaquette impurities situated along the edge. The charge doping is also taken into account. It is found that the zero-energy states may give rise to a coupling mechanism which is describable by a first-order perturbation calculus and can yield robust indirect coupling of both ferro- and antiferromagnetic character, which dominates ovet the usual RKKY mechanism. The numerical results obtained emphasize the importance of the Hubbard term and the effect of the charge doping on the coupling.
References in corpus (17)
- Electric Field Effect in Atomically Thin Carbon Films
- The electronic properties of graphene
- Emergence of magnetism in graphene materials and nanostructures
- Dynamical polarization of graphene at finite doping
- Magnetism in graphene nano-islands
- Metallic Graphene Nanodisks
- RKKY in half-filled bipartite lattices: graphene as an example
- Diluted Graphene Antiferromagnet
- RKKY Interaction in Graphene from Lattice Green's Function
- Kondo Quantum Criticality of Magnetic Adatoms in Graphene
- Indirect Exchange and Ruderman-Kittel-Kasuya-Yosida (RKKY) Interactions in Magnetically-Doped Graphene
- RKKY interaction in carbon nanotubes and graphene nanoribbons
- Electronic structure of triangular, hexagonal and round graphene flakes near the Fermi level
- Graphene Nanoribbon and Graphene Nanodisk
- RKKY interaction in gapped or doped graphene
- Indirect RKKY interaction in armchair graphene nanoribbons
- Strain-induced modulation of magnetic interactions in graphene