We study transport length scales in carbon nanotubes and graphene ribbons under the influence of Anderson disorder. We present generalized analytical expressions for the density of states, the elastic mean free path and the localization length in arbitrarily structured quantum wires. These allow us to analyze the electrical response over the full energy range, including the regions around van H...

We developed a chemical route to produce graphene nanoribbons (GNR) with width below 10 nanometers, as well as single ribbons with varying widths along their lengths or containing lattice-defined graphene junctions for potential molecular electronics. The GNRs were solution-phase-derived, stably suspended in solvents with noncovalent polymer functionalization, and exhibited ultrasmooth edges wi...

We investigated the adsorption of a single atom, hydrogen and aluminum, on single-wall carbon nanotubes from first principles. The adsorption is exothermic, and the associated binding energy varies inversely as the radius of the zigzag tube. We found that the adsorption of a single atom and related properties can be modified continuously and reversibly by the external radial deformation. The bi...

Persistent currents driven by a static magnetic flux parallel to the carbon nanotube axis are investigated. Owing to the hexagonal symmetry of graphene the Fermi contour expected for a 2D-lattice reduces to two points. However the electron or hole doping shifts the Fermi energy upwards or downwards and as a result, the shape of the Fermi surface changes. Such a hole doping leading to the Fermi ...

The interplay between the broken symmetry and the boundary conditions alters profoundly the electronic properties of carbon single-wall nanotubes ~SWNTs! of finite-lengths. For SWNTs (p ,q) characterized by p 5k1l , q5k2l , 0<l<k , and k51,2, . . . , the energy gaps for finite SWNTs belonging to a given family k exhibit strikingly similar oscillating patterns for even NT sections, but the gap m...

We explore the possibility and potential benefit of rolling a ${\mathrm{Si}}_{2}\mathrm{BN}$ sheet into single-walled nanotubes (NTs). Using density functional theory (DFT), we consider both structural stability impact on nature chemical bonding conduction. The structure is similar to carbon NTs hexagonal boron-nitride (hBN) armchair zigzag configurations with varying diameters. these confirmed...

A comprehensive picture of electromechanical responses of carbon single-walled nanotubes SWNTs is obtained using ab initio density-functional theory and self-consistent -orbital Hamiltonian. We find a linear behavior of the energy gap of zigzag SWNTs as a function of the axial strain with different slopes for compression versus extension. Observed small changes in conductance even with a substa...

Using first-principles calculations, we model the chemical vapor deposition (CVD) growth of carbon nanotubes (CNT) on nanoparticles of late-transition (Ni, Pd, Pt) and coinage (Cu, Ag, Au) metals. The process is analyzed in terms of the binding of mono- and diatomic carbon species, their diffusion pathways, and the stability of the growing CNT. We find that the diffusion pathways can be control...

Bending induced deformations in single walled carbon nanotubes with zigzag and armchair chirality have been studied computationally using a classical molecular dynamics simulation method. In this the interatomic forces have been described with Brenner’s empirical model potential. The results given by this classical model have been assessed by letting the most critical, i.e. the most deformed pa...

We study the electronic structure and energetics of carbon nanotubes with topological line defects consisting of fused pentagons and octagon rings by means of first-principles calculation in density functional theory and tight-binding molecular dynamics simulations. The tubes with the topological line defects are found to exhibit magnetic ordering where polarized electron spins are localized ar...