Theory of Magnetic Edge States in Chiral Graphene Nanoribbons

TL;DR

This paper models the electronic and magnetic properties of chiral graphene nanoribbons, revealing intrinsic magnetic edge states and how they depend on structural parameters, aligning with experimental observations.

Contribution

It introduces a comprehensive model including electron-electron interactions to analyze magnetic edge states in chiral graphene nanoribbons, highlighting their dependence on geometry and environment.

Findings

Magnetic edge states are intrinsic to chiral graphene nanoribbons.

Edge-state energy splittings depend on width and chiral angle.

Environmental screening influences magnetic properties.

Abstract

Using a model Hamiltonian approach including electron-electron interactions, we systematically investigate the electronic structure and magnetic properties of chiral graphene nanoribbons. We show that the presence of magnetic edge states is an intrinsic feature of smooth graphene nanoribbons with chiral edges, and discover a number of structure-property relations. Specifically, we study the dependence of magnetic moments and edge-state energy splittings on the nanoribbon width and chiral angle as well as the role of environmental screening effects. Our results address a recent experimental observation of signatures of magnetic ordering in chiral graphene nanoribbons and provide an avenue towards tuning their properties via the structural and environmental degrees of freedom.