Kondo and charge fluctuation resistivity due to Anderson impurities in graphene

TL;DR

This paper investigates how impurities in graphene affect electrical resistivity, focusing on the roles of Kondo and charge fluctuations, and how these depend on gate voltage and impurity location, aligning with experimental observations.

Contribution

It provides a theoretical analysis of impurity-induced resistivity in graphene, highlighting the dependence on chemical potential and impurity position, and matches experimental data quantitatively.

Findings

Charge fluctuations dominate near the Dirac point.

Kondo behavior varies with gate voltage and impurity location.

Quantitative agreement with experiments when impurity level varies linearly with chemical potential.

Abstract

Motivated by experiments on ion irradiated graphene, we compute the resistivity of graphene with dilute impurities. In the local moment regime we employ the perturbation theory up to third order in the exchange coupling to determine the behavior at high temperatures within the Kondo model. Resistivity due to charge fluctuations is obtained within the mean field approach on the Anderson impurity model. Due to the linear spectrum of the graphene the Kondo behavior is shown to depend on the gate voltage applied. The location of the impurity on the graphene sheet is an important variable determining its effect on the Kondo scale and resistivity. Our results show that for chemical potential nearby the node the charge fluctuations is responsible for the observed temperature dependence of resistivity while away from the node the spin fluctuations take over. Quantitative agreement with experimental data is achieved if the energy of the impurity level varies linearly with the chemical potential.