Theory of interedge superexchange in zigzag edge magnetism.
A graphene nanoribbon with zigzag edges has a gapped magnetic ground state with an antiferromagnetic interedge superexchange interaction. We present a theory based on asymptotic properties of the Dirac-model ribbon wave function which predicts W-2 and W-1 ribbon-width dependencies for the superexchange interaction strength and the charge gap, respectively. We find that, unlike the case of conventional atomic-scale superexchange, opposite spin orientations on opposite edges of the ribbon are favored by both kinetic and interaction energies.
Jung
J
J
Department of Physics, University of Texas at Austin, Austin, Texas 78712, USA. jeil@physics.utexas.edu
Pereg-Barnea
T
T
Macdonald
A H
AH