The Effect of Interactions on the Conductance of Graphene Nanoribbons

TL;DR

This paper investigates how electron-hole interactions influence the conductance of graphene nanoribbons, revealing that interactions can induce semiconducting behavior and modify conductance quantization.

Contribution

It introduces exactly solvable models incorporating local and non-local interactions to analyze their effects on graphene nanoribbon conductance.

Findings

Interactions turn metallic nanoribbons into semiconductors

Short-range interactions modify the conductance quantum

Models provide exact solutions for interaction effects

Abstract

We study the effects of the interaction between electrons and holes on the conductance G of quasi-one-dimensional graphene systems. We first consider as a benchmark the limit in which all interactions are negligible, recovering the predictions of the tight-binding approximation for the spectrum of the system, and the well-known result G=4 e^2/h for the lowest conductance quantum. Then we consider an exactly solvable field theoretical model in which the electro-magnetic interactions are effectively local. Finally, we use the effective field theory formalism to develop an exactly solvable model in which we also include the effect of non-local interactions. We find that such interactions turn the nominally metallic armchair graphene nanoribbon into a semi-conductor, while the short-range interactions lead to a correction to the G=4 e^2/h formula.