Interacting electrons in graphene nanoribbons in the lowest Landau level

TL;DR

This paper investigates how electron-electron interactions and spin influence the electronic and transport properties of graphene nanoribbons in a magnetic field, revealing significant changes in dispersion, formation of conductive channels, and robustness of edge states.

Contribution

It introduces a detailed analysis of electron-electron interactions in GNRs under magnetic fields, highlighting their impact on dispersion and transport properties, especially in the lowest Landau level.

Findings

Electron-electron interactions cause formation of compressible strips.

Additional conductive channels emerge in the middle of the ribbon.

Edge state transport remains robust despite disorder and spin-flipping.

Abstract

We study the effect of electron-electron interaction and spin on electronic and transport properties of gated graphene nanoribbons (GNRs) in a perpendicular magnetic field in the regime of the lowest Landau level (LL). The electron-electron interaction is taken into account using the Hartree and Hubbard approximations, and the conductance of GNRs is calculated on the basis of the recursive Greens function technique within the Landauer formalism. We demonstrate that, in comparison to the one-electron picture, electron-electron interaction leads to the drastic changes in the dispersion relation and structure of propagating states in the regime of the lowest LL showing a formation of the compressible strip and opening of additional conductive channels in the middle of the ribbon. We show that the latter are very sensitive to disorder and get scattered even if the concentration of disorder is moderate. In contrast, the edge states transport is very robust and can not be suppressed even in the presence of a strong spin-flipping.