Electronic states in nanographite ribbons with zigzag edges and zigzag carbon nanotubes are studied using the extended Hubbard model with nearest neighbor Coulomb interactions. The nearest Coulomb interactions stabilize electronic states with the opposite electric charges separated and localized along both edges. Such states are analogous as nanocondensers. Therefore, electric capacitance, defi...

In this paper we demonstrate that soliton solutions, whose existence is well known in one-dimensional (1D) model anharmonic systems, can also exist in more complex systems such as carbon nanotubes (CNT). We investigate armchair and zigzag nanotubes and show that both can be simplified to anharmonic 1D lattice models with reduced internal degrees of freedom. Because of the differences in chirali...

Nanotubes are one of the most promising functional materials in nanotechnology. Silicon nanotubes (SiNTs) have been experimentally validated; they are unique puckered nanotubular structures unlike carbon nanotubes (CNTs). Although the electronic and optical properties of SiNTs have been previously studied, their structure-related capability for electron transport has not been investigated. Here...

Based on an ab initio study, we present a structure model for a broad boron sheet, which is the precursor of boron nanotubes. Furthermore we could show that, in contrast to the armchair types, zigzag boron nanotubes have no surface tension (strain energy). As result, we predict that boron nanotubes will exhibit a chirality dependent stability, something that is unique among all nanotubular mate...

We report that freestanding films of vertically aligned carbon nanotubes exhibit super-compressible foamlike behavior. Under compression, the nanotubes collectively form zigzag buckles that can fully unfold to their original length upon load release. Compared with conventional low-density flexible foams, the nanotube films show much higher compressive strength, recovery rate, and sag factor, an...

We show that the photoluminescence intensity of single-walled carbon nanotubes is much stronger in tubes with large chiral angles--armchair tubes--because exciton resonances make the luminescence of zigzag tubes intrinsically weak. This exciton-exciton resonance depends on the electronic structure of the tubes and is found more often in nanotubes of the +1 family. Armchair tubes do not necessar...

The electronic properties of carbon nanotubes (NTs) in a uniform transverse field are investigated within a single orbital tight-binding (TB) model. For doped nanotubes, the dielectric function is found to depend not only on symmetry of the tube, but also on radius and Fermi level position. Band gap opening/closing is predicted for zigzag tubes, while it is found that armchair tubes always rema...

This paper presents a structural mechanics approach to modeling the deformation of carbon nanotubes. Fundamental to the proposed concept is the notion that a carbon nanotube is a geometrical frame-like structure and the primary bonds between two nearest-neighboring atoms act like load-bearing beam members, whereas an individual atom acts as the joint of the related load-bearing beam members. By...