Quantum conductance of graphene nanoribbons with edge defects

TL;DR

This paper investigates how edge defects and weak disorder affect the quantum conductance of graphene nanoribbons, revealing defect-induced localized states, sensitivity differences between armchair and zigzag GNRs, and disorder-induced metal-semiconductor transitions.

Contribution

It provides a detailed analysis of the impact of edge defects and disorder on GNR conductance, highlighting the differing sensitivities of armchair and zigzag configurations and the transition to semiconducting behavior.

Findings

Single edge defects cause zero-conductance dips and localized states.

Zigzag GNRs become semiconducting under weak disorder due to Anderson localization.

Armchair GNRs are less affected by weak disorder and edge defects.

Abstract

The conductance of metallic graphene nanoribbons (GNRs) with single defects and weak disorder at their edges is investigated in a tight-binding model. We find that a single edge defect will induce quasi-localized states and consequently cause zero-conductance dips. The center energies and breadths of such dips are strongly dependent on the geometry of GNRs. Armchair GNRs are much more sensitive to a vacancy than zigzag GNRs, but are less sensitive to a weak scatter. More importantly, we find that with a weak disorder, zigzag GNRs will change from metallic to semiconducting due to Anderson localization. But a weak disorder only slightly affects the conductance of armchair GNRs. The influence of edge defects on the conductance will decrease when the widths of GNRs increase.