Generic suppression of conductance quantization of interacting electrons in graphene nanoribbons in a perpendicular magnetic field

TL;DR

This paper investigates how electron interactions in graphene nanoribbons under a perpendicular magnetic field suppress conductance quantization, revealing interaction-induced band structure changes and increased backscattering.

Contribution

It demonstrates that electron interactions cause suppression of conductance quantization and form compressible strips, challenging the expectation of improved quantization in magnetic fields.

Findings

Magnetic field suppresses conductance quantization in GNRs.

Interaction-induced band modifications lead to compressible strips.

Overlap of propagating states enhances backscattering.

Abstract

The effects of electron interaction on the magnetoconductance of graphene nanoribbons (GNRs) are studied within the Hartree approximation. We find that a perpendicular magnetic field leads to a suppression instead of an expected improvement of the quantization. This suppression is traced back to interaction-induced modifications of the band structure leading to the formation of compressible strips in the middle of GNRs. It is also shown that the hard wall confinement combined with electron interaction generates overlaps between forward and backward propagating states, which may significantly enhance backscattering in realistic GNRs. The relation to available experiments is discussed.