Electronic and transport properties of kinked graphene

TL;DR

This study uses first principles calculations to explore how linear bends in graphene reduce hydrogen adsorption barriers and how kink lines influence electronic transport, proposing new methods for band gap engineering.

Contribution

The paper demonstrates that linear bends in graphene significantly lower hydrogen adsorption barriers and that kink lines can be used to engineer electronic transport properties and band gaps.

Findings

Hydrogen adsorption barrier reduced by 15% at bends with 20 Å radius.

Kink lines act as barriers to electron transport.

Pseudo-ribbon structures enable band gap engineering.

Abstract

Local curvature, or bending, of a graphene sheet is known to increase the chemical reactivity presenting an opportunity for templated chemical functionalization. Using first principles calculations based on density functional theory (DFT) we investigate the reduction of the reaction barrier for adsorption of atomic hydrogen at linear bends in graphene. We find a significant lowering (15%) for realistic radii of curvature (20 {\AA}), and that adsorption along the linear bend leads to a stable linear kink. We compute the electronic transport properties of individual and multiple kink-lines, and demonstrate how these act as efficient barriers for electron transport. In particular, two parallel kink-lines form a graphene pseudo-nanoribbon structure with a semi-metallic/semi-conducting electronic structure closely related to the corresponding isolated ribbons; the ribbon band gap translates into a transport gap for transport across the kink lines. We finally consider pseudo-ribbon based heterostructures, and propose that such structures present a novel approach for band gap engineering in nanostructured graphene.