A molecular simulation analysis of producing monatomic carbon chains by stretchingultranarrow graphene nanoribbons

Abstract

Atomistic simulations were utilized to develop fundamental insights regarding theelongation process starting from ultranarrow graphene nanoribbons (GNRs) and resultingin monatomic carbon chains (MACCs). There are three key findings. First, we demonstratethat complete, elongated, and stable MACCs with fracture strains exceeding 100% can beformed from both ultranarrow armchair and zigzag GNRs. Second, we demonstrate thatthe deformation processes leading to the MACCs have strong chirality dependence.Specifically, armchair GNRs first form DNA-like chains, then develop into monatomicchains by passing through an intermediate configuration in which monatomic chainsections are separated by two-atom attachments. In contrast, zigzag GNRs formrope-ladder-like chains through a process in which the carbon hexagons are firstelongated into rectangles; these rectangles eventually coalesce into monatomicchains through a novel triangle–pentagon deformation structure under furthertensile deformation. Finally, we show that the width of GNRs plays an importantrole in the formation of MACCs, and that the ultranarrow GNRs facilitate theformation of full MACCs. The present work should be of considerable interest due tothe experimentally demonstrated feasibility of using narrow GNRs to fabricatenovel nanoelectronic components based upon monatomic chains of carbon atoms.