Theory of interedge superexchange in zigzag edge magnetism.

Spin-polarized transport through a zigzag-edge graphene flake embedded between two armchair nanoribbons electrodes

We study the coherent spin-polarized transport through a zigzag-edge graphene flake (ZGF), using Hubbard model in the nearest neighbor approximation within the framework of the Green function’s technique and Landauer formalism. The system considered consists of electrode/ (ZGF)/electrode, in which the electrodes are chosen to be armchair nanoribbons. The study was performed for two types of ele...

Edge magnetism of Heisenberg model on honeycomb lattice

Edge magnetism in graphene sparks intense theoretical and experimental interests. In the previous study, we demonstrated the existence of collective excitations at the zigzag edge of the honeycomb lattice with long-ranged Néel order. By employing the Schwinger-boson approach, we show that the edge magnons remain robust even when the long-ranged order is destroyed by spin fluctuations. Furthermo...

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...

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/...

Electron spin magnetism of zigzag graphene nanoribbon edge states