Edge magnetization and local density of states in chiral nanoribbons

TL;DR

This paper investigates how edge magnetization and local density of states in chiral graphene nanoribbons are influenced by band structure modifications and chirality, providing insights consistent with recent experimental observations.

Contribution

It introduces a detailed analysis of edge magnetization in chiral nanoribbons considering next-nearest hopping effects, expanding understanding of their magnetic properties.

Findings

Edge magnetization is weakly dependent on nanoribbon width for sufficiently wide ribbons.

Next-nearest hopping significantly alters the band structure and magnetic behavior.

Local density of states peaks can be explained without interedge antiferromagnetic interactions.

Abstract

We study the edge magnetization and the local density of states of chiral graphene nanoribbons using a {\pi}-orbital Hubbard model in the mean-field approximation. We show that the inclusion of a realistic next-nearest hopping term in the tight-binding Hamiltonian changes the graphene nanoribbons band structure significantly and affects its magnetic properties. We study the behavior of the edge magnetization upon departing from half filling as a function of the nanoribbon chirality and width. We find that the edge magnetization depends very weakly in the nanoribbon width, regardless of chirality as long as the ribbon is sufficiently wide. We compare our results to recent scanning tunneling microscopy experiments reporting signatures of magnetic ordering in chiral nanoribbons and provide an interpretation for the observed peaks in the local density of states, that does not depend on the antiferromagnetic interedge interaction.