Switching behavior of carbon chains bridging graphene nanoribbons: effects of uniaxial strain.

Recently, several experiments demonstrated the stability of chain-like carbon nanowires bridged between graphene nanoribbons, paving the way for potential applications in nanodevices. On the basis of density functional tight-binding calculations, we demonstrated switching for chains terminated with a five-membered ring under an applied strain, serving as a model for morphological changes in realistic materials. Electron transport calculations showed an increase of up to 100% in the output current, achieved at a reverse bias voltage of -2 V and an applied strain of just 1.5%. Structural analysis suggested that the switching is driven by conformational changes, where in our case is triggered by the formation and annihilation of a five-membered ring at the interface of the chain-graphene edge. In addition, we showed that a five-membered ring can easily be formed at the interface under a source-drain bias or through a gate voltage. This mechanism can serve as an explanation of experimentally observed conductance for the materials.