Adatoms and Anderson localization in graphene

TL;DR

This paper investigates how adatoms induce Anderson localization in graphene, revealing conditions under which localization occurs or is suppressed, leading to potential metallic states with unique properties.

Contribution

It demonstrates that certain adatoms cause Anderson localization near the Dirac point, while others suppress it, identifying conditions for observing the Anderson transition in graphene.

Findings

Adatoms at the center of honeycomb plaquettes induce localization near the Dirac point.

A symmetry class of adatoms suppresses localization, resulting in a metallic state.

Experimental conditions for observing the Anderson transition are identified.

Abstract

We address the nature of the disordered state that results from the adsorption of adatoms in graphene. For adatoms that sit at the center of the honeycomb plaquette, as in the case of most transition metals, we show that the ones that form a zero-energy resonant state lead to Anderson localization in the vicinity of the Dirac point. Among those, we show that there is a symmetry class of adatoms where Anderson localization is suppressed, leading to an exotic metallic state with large and rare charge droplets, that localizes only at the Dirac point. We identify the experimental conditions for the observation of the Anderson transition for adatoms in graphene.