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...

Using first-principles methods, we study the physicochemical properties such as the binding mechanism and band offset for single-wall zigzag nanotubes on InAs. While the tubes maintain their structural and electronic integrity, binding energies as large as 0.4 eV per site are obtained. Except for semiconducting tubes on the polar surfaces, an approximate universal band alignment is also obtaine...

Searching for novel functional carbon materials is an enduring topic of scientific investigations, due to its diversity of bonds, including sp-, sp(2)-, and sp(3)-hybridized bonds. Here we predict a new carbon allotrope, bct-C12 with the body-centered tetragonal I4/mcm symmetry, from the compression of carbon nanotubes. In particular, this structure behaviors as the Dirac fermions in the kz dir...

The edge states and optical transition energies in carbon nanoribbons are investigated with density-functional calculations. While the ground state of zigzag ribbons is spin polarized, defects at the edges destroy spin polarization and lead to a nonmagnetic ground state. Scanning tunneling spectroscopy will thus show different features depending on edge quality. Optical transition energies in n...

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...

The algorithm here described concerns generation, visualization, and modification of molecular nanostructures of single-walled nanotubes (NTs) of particular configurations (armchair, zipper, multiple zipper, zigzag, or chiral) by means of a Graphical User Interface (GUI). NTs are made from a carbon graphene sheet created according to certain parameters defining required nanostructures. Generate...

We perform {\it ab initio} many-body calculations to investigate the exciton shift current in small diameter zigzag BN nanotubes and also single sheet, using GW plus Bethe-Salpeter equation (GW-BSE) method with newly developed efficient algorithms. Our GW-BSE reveal a giant in-gap peak spectrum all studied systems due excitation of A exciton. The value excitonic is more than three times larger ...

Based on the constructed atomistic models of graphene/nanotube films with different numbers nanotubes in supercells, we carried out silico studies regularities nonuniform density distribution, which determine presence an island structure such films. As a result quantum molecular dynamics modeling, it is found that thin tubes subnanometer diameter are enveloped graphene sheets, makes them energe...

Phenine Nanotubes (PhNT) are cylinder-shaped molecules synthetized from 1,3,5-trisubstituted benzene ring building blocks that can form tubular segments of different sizes. Small nanotube have been recently synthetized, and efforts being made to increase the nanotubes’ length by adding more “phenine” units. To authors’ best knowledge, a complete characterization mechanical properties these nano...