Geometric, magnetic and electronic properties of folded graphene nanoribbons

TL;DR

This study uses first-principles calculations to explore how stacking, curvature, and edges influence the geometric, magnetic, and electronic properties of folded graphene nanoribbons, revealing stability patterns and diverse electronic behaviors.

Contribution

It provides a detailed analysis of the stability, electronic structure, and density of states of folded graphene nanoribbons based on their stacking and edge configurations, which was not previously comprehensively studied.

Findings

AB stacking is more stable for zigzag FGNRs.

Most FGNRs are direct-gap semiconductors.

Edge-edge interactions can induce metallic bands in certain configurations.

Abstract

Geometric and electronic properties of folded graphene nanoribbons (FGNRs) are investigated by first-principles calculations. These properties are mainly dominated by the competition or cooperation among stacking, curvature and edge effects. For the zigzag FGNRs, the more stable structures are revealed to be AB stackings, while for the armchair types, AA" stackings are more stable. The interlayer interactions and hybridization of four orbitals lead to smaller energy gaps, anti-crossing bands, and more band-edge states. Specifically, the broken mirror symmetry in the odd-AB stacked zigzag FGNRs is responsible for the spin-up and spin-down splitting subbands. All FGNRs are direct-gap semiconductors except that the edge-edge interactions cause the even-AA stacked zigzag FGNRs to exhibit a pair of metallic linear bands. The width-dependent energy gaps in the armchair FGNRs can be classified into six groups. Furthermore, there exist rich features in density of states, including the form, number, intensity and energy of the special structures.