The Physics of Kondo Impurities in Graphene

TL;DR

This paper reviews the theoretical understanding of the Kondo effect in graphene, focusing on impurity models, quantum phase transitions, and experimental comparisons, highlighting the unique physics due to graphene's Dirac electrons.

Contribution

It provides a comprehensive theoretical analysis of magnetic impurities in graphene, including impurity creation methods, quantum phase transitions, and connections to other quantum impurity systems.

Findings

Effective impurity models describe magnetic moments in graphene.

Quantum phase transitions depend on carrier doping.

Experimental data supports theoretical models.

Abstract

This article summarizes our understanding of the Kondo effect in graphene, primarily from a theoretical perspective. We shall describe different ways to create magnetic moments in graphene, either by adatom deposition or via defects. For dilute moments, the theoretical description is in terms of effective Anderson or Kondo impurity models coupled to graphene's Dirac electrons. We shall discuss in detail the physics of these models, including their quantum phase transitions and the effect of carrier doping, and confront this with existing experimental data. Finally, we point out connections to other quantum impurity problems, e.g., in unconventional superconductors, topological insulators, and quantum spin liquids.