Role of lattice registry in the full collapse and twist formation of carbon nanotubes

The effect of interlayer lattice registry on the formation of fully collapsed single wall carbon nanotubes (SWCNTs) was studied via atomistic simulation. It was found that a fully collapsed SWCNT could adopt various structural morphologies, such as a straight ribbon, a warping ribbon, or even a twisted ribbon. Such structural formations depended on the degree of commensurance between the lattice structures of the adhering layers in a collapsed SWCNT, thus the chirality of the SWCNT. The modeling result was further corroborated with a simple analysis of the system energy difference among graphitic double layer structures with different interlayer lattice registry, and with the experimental observation of freestanding, twisted, and collapsed nanotubes.

Figure 1

A stability map for the deformation of armchair CNTs.

Figure 2

The transmission electron microcopy images of three types of collapsed multiwalled carbon nanotube (MWCNT); (a) a doubly supported, twisted, and fully collapsed MWCNT; (b) a purely flat and fully collapsed MWCNT; and (c) a cantilevered, twisted, and fully collapsed MWCNT.

Figure 3

(Color online) The collapsed CNTs and their projected lattice views in the ribbon region with and without the consideration of the lattice registry effect.

Figure 4

(Color online) The system energy vs the alignment angle for two parallel graphenes shown in the inset.