Zero Landau level in folded graphene nanoribbons

TL;DR

This paper demonstrates that in folded graphene nanoribbons, zero Landau level edge states are perfectly transmitted across folds due to symmetry, leading to suppressed backscattering in the quantum Hall regime.

Contribution

It reveals that zero energy edge states in metallic nanoribbons are perfectly transmitted across folds, independent of geometry or magnetic field, due to symmetry and orthogonality.

Findings

Zero Landau level edge states are perfectly transmitted across folds.

Backscattering is suppressed due to orthogonality of channels.

Transmission is independent of fold geometry and orientation.

Abstract

Graphene nanoribbons can be folded into a double layer system keeping the two layers decoupled. In the Quantum Hall regime folds behave as a new type of Hall bar edge. We show that the symmetry properties of the zero Landau level in metallic nanoribbons dictate that the zero energy edge states traversing a fold are perfectly transmitted onto the opposite layer. This result is valid irrespective of fold geometry, magnetic field strength and crystallographic orientation of the nanoribbon. Backscattering suppression on the N=0 Hall plateau is ultimately due to the orthogonality of forward and backward channels, much like in the Klein paradox.