Effects of random atomic disorder on the magnetic stability of graphene nanoribbons with zigzag edges

TL;DR

This study examines how random atomic defects influence the magnetic stability of zigzag-edged graphene nanoribbons, revealing that balanced defects do not alter antiferromagnetic edge states and can enhance overall magnetic stability.

Contribution

It provides new insights into the robustness of magnetic properties in graphene nanoribbons under atomic disorder using an extended mean-field Hubbard model.

Findings

Antiferromagnetic edge states remain stable with balanced defects.

Single spin flip excitations are more likely at low defect concentrations.

Overall magnetic stability is improved compared to ferromagnetic phase.

Abstract

We investigate the effects of randomly distributed atomic defects on the magnetic properties of graphene nanoribbons with zigzag edges using an extended mean-field Hubbard model. For a balanced defect distribution among the sublattices of the honeycomb lattice in the bulk region of the ribbon, the ground state antiferromagnetism of the edge states remains unaffected. By analyzing the excitation spectrum, we show that while the antiferromagnetic ground state is susceptible to single spin flip excitations from edge states to magnetic defect states at low defect concentrations, it's overall stability is enhanced with respect to the ferromagnetic phase.