Interplay of Edge-State Spins and σ-Dangling Bond Spins in the Magnetic Structure of Nanographene

Abstract

Nanographene has magnetic edge states of π-electron origin at the zigzag edge due to the broken symmetry of massless Dirac fermion on the graphene hexagonal bipartite lattice. The destruction of the graphene π-conjugated system by fluorination creates σ-dangling bond spins in the interior of the graphene sheet. The magnetic structure is investigated for nanographene-network-based carbon with a focus on the interplay between the edge-state spins and σ-dangling bond spins. The edge-state spins of an arbitrary shaped nanographene form a ferrimagnetic structure under the cooperation of strong intra-zigzag-edge ferromagnetic interaction and intermediate strength inter-zigzag edge ferromagntic/antiferromagnetic interaction. The σ-dangling bond spins are free from exchange interaction, in contrast to the edge-state spins.

Keywords:

• Nanographene
• magnetic property
• edge state spin
• σ-dangling bond spin
• ferrimagnetic structure

Acknowledgments

The authors acknowledge support from Grant-in-Aid for Scientific Research No. 20001006 from the Ministry of Education, Culture, Sports, Science and Technology, Japan.