Impurity resonance effects in graphene $vs$ impurity location, concentration and sublattice occupation

TL;DR

This paper investigates how impurity location, concentration, and sublattice occupation affect the electronic properties of graphene, revealing complex spectral phenomena and potential implications for electronic behavior and phase transitions.

Contribution

It provides a detailed analytical and numerical study of impurity effects in graphene, considering various impurity types and positions, which advances understanding of disorder-induced spectral phenomena.

Findings

Impurities induce resonances, quasi-gaps, and impurity sub-bands in graphene.

Impurity effects depend strongly on their location and concentration.

Results suggest possible control of electronic phases via impurity engineering.

Abstract

Unique electronic band structure of graphene with its semi-metallic features near the charge neutrality point is sensitive to impurity effects. Using the Lifshitz and Anderson impurity models, we study in detail the disorder induced spectral phenomena in the electronic band structure of graphene, namely, the formation of resonances, quasi-gaps, bound states, impurity sub-bands, and their overall impact on the electronic band restructuring and the associated Mott-like metal-insulator transitions. We perform systematic analytical and numerical study for realistic impurities, both substitutional and adsorbed, focusing on those effects that stem from the impurity adatoms locations (top, bridge, and hollow positions), concentration, host sublattice occupation, perturbation strengths, etc. Possible experimental and practical implications are discussed as well.