Ab Initio Investigations Of The Transport Properties Of Haeckelite Nanotubes And Graphene Junctions

1. Ab initio investigations of the transport properties of Haeckelite nanotubesA systematic investigation of the electronic transport properties of Haeckelite nanotubes using ab initio calculation is presented. The Haeckelite nanotube is coupled with Haeckelite nanotubes and bulk Au electrodes, respectively. When the Haeckelite nanotube is coupled with Haeckelite nanotubes, negative differential resistance and nonlinear conduction phenomena have been observed in the simulated I-V curves. However, negative differential resistance is disappeared when the Haeckelite nanotube is coupled with bulk Au electrodes. Our results suggest that this behavior is attributable to the band mismatch between left and right electrodes, which implies that some intriguing electronic transport characteristics could be realized by using nanoscale electrodes.2. Computational design of junctions between carbon nanotubes and graphene nanoribbonsUsing first-principles density functional theory calculations, various junction models constructed from different carbon nanotube and graphene nanoribbon units via covalent linkage have been envisioned. These models consist of linear, T and H-shaped junctions within the connection modes between carbon nanotube and graphene nanoribbon units. The electronic transport properties of different junctions have been systematically investigated by using non-equilibrium Green function. The simulation results suggested that:(i) The peptide is rigid while the disulfide is flexible.(ii) For peptide junctions, AE will significantly heighten while the number of linkages increases. For disulfide junctions, AE is mainly decided by the number of linkages. The armchair CNT-GNR junctions tend to be exothermic, while zigzag CNT-GNR junctions tend to be endothermic.(iii) Disulfide linkage has better conductivity than peptide, and the linkages will strongly modify the electronic properties.(iv) For T-junctions, the transport properties are mostly determined by the main chain; the effect of the branch is minor. (v) For H-junctions, conductivity between different graphene layers is poor. Based on the H-junction structure, a promising three-dimensional network has been envisioned, which could be the archetype of next-generational carbon-based microelectronic circuits.