The low-frequency electronic excitations in double-walled armchair carbon nanotubes are studied within the random-phase approximation. The intertube atomic overlaps significantly affect the low-energy bands and thus enrich the low-frequency single-particle excitations and collective excitations. They induce more plasmon modes, reduce the plasmon strength, and change acoustic plasmons into optic...

Let G be a graph. The distance d(u,v) between the vertices u and v of the graph G is equal to the length of a shortest path that connects u and v. The Wiener index W(G) is the sum of all distances between vertices of G, whereas the hyper-Wiener index WW(G) is defined as WW(G)=12W(G)+12@?"{"u","v"}"@?"V"("G")d (u,v)^2. In this paper the hyper-Wiener indices of the Cartesian product, composition,...

We investigate the nitrogen substitutional impurity in semiconducting zigzag and metallic armchair single-wall carbon nanotubes using ab initio density functional theory. At low concentrations (less than 1 at. %), the defect state in a semiconducting tube becomes spatially localized and develops a flat energy level in the band gap. Such a localized state makes the impurity site chemically and e...

A combination of ab initio simulations and linear-scaling Green’s functions techniques is used to analyze the transport properties of long (up to one micron) carbon nanotubes with realistic disorder. The energetics and the influence of single defects (monoand di-vacancies) on the electronic and transport properties of single-walled armchair carbon nanotubes are analyzed as a function of the tub...

Lithium storage and capture are of particular importance for the development new technology in electric vehicles portable electronics. Nanotubes (NTs) among many porous nanomaterials offered as potential candidates lithium storage. In this paper, we adopt a continuum approach together with Lennard–Jones function to determine minimum interaction energies atoms boron nitride nanotubes (BNNTs) car...

Disorder effects on density of states and electronic conduction in metallic carbon nanotubes are analyzed by a tight binding model with Gaussian bond disorder. Metallic armchair and zigzag nanotubes are considered. We obtain a conductance which becomes smaller by the factor of the inverse of a few from that of the clean nanotube. This decrease mainly comes from lattice fluctuations of the width...