Graphene-based sp2-carbon nanostructures such as carbon nanotubes and nanofibers can fail near their ideal strengths due to their exceedingly small dimensions. We have calculated the phonon spectra of graphene as a function of uniaxial tension by density functional perturbation theory to assess the first occurrence of phonon instability on the strain path, which controls the strength of a defec...

We study the transport properties of disordered electron systems that contain perfectly conducting channels. Two quantum network models that belong to different universality classes, unitary and symplectic, are simulated numerically. The perfectly conducting channel in the unitary class can be realized in zigzag graphene nano-ribbons and that in the symplectic class is known to appear in metall...

Using ab initio local spin-density-functional formalism, we study the occurrence of spin polarization in quasi-one-dimensional heterostructured C/BN nanotubes. At the zigzag boundary connecting carbon and boron nitride segments of tubes, we find atomiclike states that acquire magnetization when partly filled. Whereas individual C/BN heterojunctions can be used to spin-polarize electrons during ...

The ability to control the conductance of single molecules will have a major impact in nanoscale electronics. Azobenzene, a molecule that changes conformation as a result of a trans/cis transition when exposed to radiation, could form the basis of a light-driven molecular switch. It is therefore crucial to clarify the electrical transport characteristics of this molecule. Here, we investigate, ...

Structurally uniform and chirality-pure single-wall carbon nanotubes are highly desired for both fundamental study and many of their technological applications, such as electronics, optoelectronics, and biomedical imaging. Considerable efforts have been invested in the synthesis of nanotubes with defined chiralities by tuning the growth recipes but the approach has only limited success. Recentl...

in this study, kinetics and mechanism of the sulfur dioxide adsorption on the single-walled carbon nanotubes (cnt) are investigated. three single-walled carbon nanotubes, including the armchair (6,6), chiral (6,5) and zigzag (6,0) cnts were chosen as the models and the different orientations of so2 molecule relative to the cnt axis were considered. the b3lyp functional within the 6-31g(d) basis...

A Hamiltonian is derived for a zigzag carbon nanotube with an arbitrary number of weak electron-electron charge and spin interactions, which become significant in ultraclean systems. The renormalization group and bosonization are used to determine the ground-state phase diagram. Our phase diagram contains some exotic phases which have not previously been predicted in carbon nanotubes with physi...

By employing the theoretical method based on tight-binding, we study electronic band structure of single-wall carbon nanotube (CNT) superlattices, which the system is the made of the junction between the zigzag and armchair carbon nanotubes. Exactly at the place of connection, it is appeared the pentagon–heptagon pairs as topological defect in carbon hexagonal network. The calculations are base...