One-dimensional quantum channel in a graphene line defect

TL;DR

This paper investigates a line defect in graphene that creates a controllable one-dimensional quantum channel, demonstrating that the gapless state can be manipulated via gate voltage and is robust against various structural parameters.

Contribution

It introduces a method to construct and control a quantum channel in graphene using a line defect with sublattice symmetry breaking, supported by conductance calculations.

Findings

A gapless state exists for mirror-symmetric configurations.

The gapless state is independent of ribbon width and defect location.

Gate voltage can tune the quantum channel.

Abstract

Using a tight-binding model, we study a line defect in graphene where a bulk energy gap is opened by sublattice symmetry breaking. It is found that sublattice symmetry breaking may induce many configurations that correspond to different band spectra. In particular, a gapless state is observed for a configuration which hold a mirror symmetry with respect to the line defect. We find that this gapless state originates from the line defect and is independent of the width of the graphene ribbon, the location of the line defect, and the potentials in the edges of the ribbon. In particular, the gapless state can be controlled by the gate voltage embedded below the line defect. Finally, this result is supported with conductance calculations. This study shows how a quantum channel could be constructed using a line defect, and how the quantum channel can be controlled by tuning the gate voltage embedded below the line defect.