Defect Induced Resonances and Magnetic Patterns in Graphene

TL;DR

This study explores how point and line defects in graphene influence electronic states and magnetic patterns, revealing defect-specific resonance states and magnetic distributions that depend on defect type and strength.

Contribution

It provides a detailed analysis of defect-induced electronic and magnetic phenomena in graphene using a Hubbard model and mean field theory, highlighting new defect-related magnetic patterns.

Findings

Resonance bound states near Dirac points depend on scattering potential strength.

Magnetic moments are enhanced around defect clusters and line defects.

Line defect type influences the magnetic pattern amplitude and localization.

Abstract

We investigate the effects of point and line defects in monolayer graphene within the framework of the Hubbard model, using a self-consistent mean field theory. These defects are found to induce characteristic patterns into the electronic density of states and cause non-uniform distributions of magnetic moments in the vicinity of the impurity sites. Specifically, defect induced resonance bound states in the local density of states are observed at energies close to the Dirac points. The magnitudes of the frequencies of these resonance states are shown to decrease with the strength of the scattering potential, whereas their amplitudes decay algebraically with increasing distance from the defect. For the case of defect clusters, we observe that with increasing defect cluster size the local magnetic moments in the vicinity of the cluster center are strongly enhanced. Furthermore, non-trivial impurity induced magnetic patterns are observed in the presence of line defects: zigzag line defects are found to introduce stronger-amplitude magnetic patterns than armchair line defects. When the scattering strength of these topological defects is increased, the induced patterns of magnetic moments become more strongly localized.