Theory of Interedge Superexchange in Zigzag Edge Magnetism

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 conve...

Electron spin magnetism of zigzag graphene nanoribbon edge states

Limited robustness of edge magnetism in zigzag graphene nanoribbons with electrodes.

It is shown that apart from well-known factors, like temperature, substrate, and edge reconstruction effects, also the presence of external contacts is destructive for the formation of magnetic moments at the edges of graphene nanoribbons (GNRs). The edge magnetism gradually decreases when graphene/electrode interfaces become more and more transparent for electrons. In addition to the graphene/...

Edge state magnetism in zigzag-interfaced graphene via spin susceptibility measurements

Development of graphene spintronic devices relies on transforming it into a material with a spin order. Attempts to make graphene magnetic by introducing zigzag edge states have failed due to energetically unstable structure of torn zigzag edges. Here, we report on the formation of nanoridges, i.e., stable crystallographically oriented fluorine monoatomic chains, and provide experimental eviden...

Preserving the Edge Magnetism of Zigzag Graphene Nanoribbons by Ethylene Termination: Insight by Clar's Rule

By means of density functional theory computations, we demonstrated that C2H4 is the ideal terminal group for zigzag graphene nanoribbons (zGNRs) in terms of preserving the edge magnetism with experimental feasibility. The C2H4 terminated zGNRs (C2H4-zGNRs) with pure sp(2) coordinated edges can be stabilized at rather mild experimental conditions, and meanwhile reproduce the electronic and magn...