Defect-Induced Kondo Effect in graphene: Role of Localized State of $\pi$ Electrons

Abstract

We discuss a role of the localized $\pi$ orbital, which exists around the defect, on the defect-induced Kondo effect in graphene by a numerical renormalization group study. We find that the localized $\pi$ orbital assists this Kondo effect, and the Kondo temperature is sensitive to the broadening of the localized $\pi$ orbital. Secondly, we focus on the negative magnetoresistance of this Kondo effect. In the experimental result, it has been shown that the negative magnetoresistance is ten times larger than the usual Kondo effect. In order to clarify the mechanism of the "magnetic sensitive" Kondo effect, as a first step, we study an orbital magnetic field dependence of the localized $\pi$ orbital by a tight-binding model with a Peierls phase. We find that as the magnetic field increases, the spectral width of the localized $\pi$ orbital increases and the local DOS at the Fermi level decreases. Since the Kondo temperature is strongly dependent of the broadening of the localized $\pi$ orbital, it is expected that this Kondo effect is sensitive to the orbital magnetic field as observed in the experiment.

10 pages, 6 figures. To be published in J. Phys. Conf. Series

References in corpus (13)

• The numerical renormalization group method for quantum impurity systems
• Magnetism in Graphene Induced by Single-Atom Defects
• Emergence of magnetism in graphene materials and nanostructures
• Induced Magnetic Ordering by Proton Irradiation in Graphite
• Disorder Induced Localized States in Graphene
• Modeling disorder in graphene
• The Physics of Kondo Impurities in Graphene
• Phase transitions in the pseudogap Anderson and Kondo models: Critical dimensions, renormalization group, and local-moment criticality
• Tuning Kondo physics in Graphene with gate voltage
• Gate-controlled Kondo screening in graphene: Quantum criticality and electron-hole asymmetry
• Interactions and magnetic moments near vacancies and resonant impurities in graphene
• Block Lanczos density-matrix renormalization group method for general Anderson impurity models: Application to magnetic impurity problems in graphene
• Theory of Defect-Induced Kondo Effect in Graphene: Numerical Renormalization Group Study