Chemistry at the edges of saturated graphene nanoribbons can cause ribbons to leave the plane and form three-dimensional helical structures. Calculations, based on density functional theory and enabled by adopting helical symmetry, show that F-terminated armchair ribbons are intrinsically twisted in helices, unlike flat H-terminated strips. Twisting ribbons of either termination couple the conduction and valence bands, resulting in band gap modulation.
View Article and Find Full Text PDFIn equilibrium, graphene nanostrips, with hydrogens sp2-bonded to carbons along their zigzag edges, are expected to exhibit a spin-polarized ground state. However, in the presence of a ballistic current, we find that there exists a voltage range over which both spin-polarized and spin-unpolarized nanostrip states are stable. These states can represent a bit in a binary memory device that could be switched through the applied bias and read by measuring the current through the nanostrip.
View Article and Find Full Text PDFMany single-wall carbon nanotube (SWNT) properties near the Fermi level were successfully predicted using a nearest-neighbor tight-binding model characterized by a single parameter, V1. We show however that this model fails for armchair-edge graphene nanostrips due to interactions directly across hexagons. These same interactions are found largely hidden in the description of SWNTs, where they renormalize V1 leaving previous nearest-neighbor model SWNT results largely intact while resolving a long-standing puzzle regarding the magnitude of V1.
View Article and Find Full Text PDFThe oxidation of aluminum nanoparticles is studied with classical molecular dynamics and the Streitz-Mintmire (Streitz, F. H.; Mintmire, J.
View Article and Find Full Text PDFSingle-wall carbon nanotubes (SWCNTs) represent an excellent example of materials by design with many of their outstanding properties predicted by theory prior to their synthesis. Both experimental and theoretical work on these novel nanowires continue to increase at a breathtaking pace. Herein we describe some of their fundamental properties on which much of this work is built.
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