We investigate the band-gap modiication by collapsing deformation in C, BN, and BC3 nanotubes through rst-principles pseudopotential calculations. Semiconductor-metal transitions occur when zigzag C and armchair BC3 nanotubes undergo collapsing deformation, while in zigzag BN tubes, a variation of band gaps from 5 to 2 eV is found. On the other hand, the band gaps of armchair BN and zigzag BC3 ...

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 have investigated the electronic structure and carrier mobility of armchair and zigzag single-walled MoS₂ nanotubes using density functional theory combined with Boltzmann transport method with relaxation time approximation. It is shown that armchair nanotubes are indirect bandgap semiconductors, while zigzag nanotubes are direct ones. The band gaps of single-walled MoS₂ nanotubes are along ...

Using density-functional theory the stability of armchair and zigzag single-walled carbon nanotubes and graphene nanoribbons was investigated. We found that the stability of armchair and zigzag nanotubes has different linear dependence with regard to their length, with switches in the most stable chirality occurring at specific lengths for each nanotube series. We explain these dependencies by ...

the reaction mechanism between (h2c) and (7, 0), zigzag single-walled carbon nanotubes(zswcnts) on two different orientation of c-c have been studied by semi empirical am!method. the activation barriers of (h2c) adding to (7, 0) zswcnt are computed and compared.the effects of diameters of zigzag swcnt on their binding energies were studied

   In this study the adsorption of selenium molecule (Se2) on the outer surface of zigzag (5,0), (8,0) and (10,0) carbon nanotubes has been investigated. We examined number adsorbed orientations as well as different adsorption sites on nanotubes. The adsorption energies, equilibrium distances, energy differences between the highest occupied molecular orbital (HOMO) and lowest uno...

In this paper, we show that Krypton atoms form a commensurate solid (CS) phase with a fractional coverage of one krypton atom per every four carbons on zigzag carbon nanotubes. This is a unique phase, different from the √ 3×√3R30◦ CS monolayer formed on graphite, which has a lower coverage of one krypton atom per every six carbons. Our prediction disagreeswith experiments that observe in nanotu...

Metallic single-walled carbon nanotubes have been proposed to be good one-dimensional conductors. However, the finite curvature of the graphene sheet that forms the nanotubes and the broken symmetry due to the local environment may modify their electronic properties. We used low-temperature atomically resolved scanning tunneling microscopy to investigate zigzag and armchair nanotubes, both thou...