Self-consistent model of edge doping in graphene

TL;DR

This paper develops a self-consistent tight-binding model to analyze how edge doping in graphene affects charge transfer and doping efficiency, revealing oscillations related to edge chirality and sublattice position.

Contribution

It introduces a novel self-consistent model combined with Greens function techniques to study edge doping effects in large graphene structures, accounting for electron-electron interactions.

Findings

Doping efficiency oscillates with sublattice position near edges.

Pronounced signatures of edges are observed in the local impurity density of states.

Edge chirality significantly influences doping behavior.

Abstract

Dopants positioned near edges in nanostructured graphene behave differently from bulk dopants. Most notable, the amount of charge transferred to delocalized states (i.e. doping efficiency) depends on position as well as edge chirality. We apply a self-consistent tight-binding model to analyze this problem focusing on substitutional nitrogen and boron doping. Using a Greens function technique, very large structures can be studied and artificial interactions between dopants in periodically repeated simulations cells are avoided. We find pronounced signatures of edges in the local impurity density of states. Importantly, the doping efficiency is found to oscillate with sublattice position, in particular, for dopants near zigzag edges. Finally, to assess the effect of electron-electron interactions, we compute the self-energy corrected Greens function.