Silica nanotube multi-terminal junctions as a coating for carbon nanotube junctions

The possibility of coating carbon nanotube junctions with single-walled, square-lattice silica nanotubes is considered. We describe the topology of junctions of such tubes, based on the generalized Euler formula for a tetragonal lattice with trigonal, pentagonal, and hexagonal topological defects. The types of silica nanotubes best fitting the considered carbon nanotube types are determined using a classical interatomic force field. The influence of the silica coating on the electronic properties of the carbon nanotube is evaluated using semiempirical Paramagnetic Model 3 (PM3) method calculations. It is found that the electronic properties of the carbon nanotube near the Fermi level are not changed considerably. Finally, we propose some examples of SiO2-C composite T-, Y-, and X-junction structures.