Carbon nanotube adsorbed on a hydrogenated Si-rich $\beta \text{−}\mathrm{Si}\mathrm{C}\left(100\right)$ $(3\times 2)$ surface: First-principles pseudopotential calculations

Single wall carbon nanotubes (SWCN’s) have attracted scientific interest as a result of their remarkable mechanical and electrical properties. Metallic SWCN’s can carry electrical current due to $\pi$ electrons propagating along their graphitelike surface. This work theoretically considers the effects resulting from the possibility of connecting nanotubes to a partially hydrogenated Si-rich $\beta \text{−}\mathrm{Si}\mathrm{C}\left(100\right)$ $(3\times 2)$ surface. This is done with the perspective that they can improve the metallic character of the surface. Calculations were performed using a first-principles pseudopotential methodology within the density-functional theory and local-density approximation. Results indicates the formation of a covalent bond between nanotube carbon atoms and surface silicon atoms. The structural and electronic properties of this theoretical system are presented and comparison with previous calculations for related systems is also done.

Figure 1

(Color online) Structure of the hydrogen saturated Si-rich $\beta \text{−}\mathrm{Si}\mathrm{C}\left(100\right)$ $(3\times 2)$ surface: (a) top view; (b) side view, with C atoms [not shown in (a)] on the fourth layer. For adsorption of the SWCN the hydrogen atoms bounded to the silicon atoms of the first layer were removed.

Figure 2

(Color online) Slab of the hydrogen partially saturated Si-rich $\beta \text{−}\mathrm{Si}\mathrm{C}\left(100\right)$ $(3\times 2)$ surface: (a) top view showing three Si planes; (b) side view, showing four planes, with C atoms [not shown in (a)] below the third-layer Si atoms.

Figure 3

(Color online) SWCN on hydrogen partially hydrogenated Si-rich $\beta \text{−}\mathrm{Si}\mathrm{C}\left(100\right)$ $(3\times 2)$ surface: (a) front view; (b) side view.

Figure 4

(Color online) Total electronic charge distribution. (a) front view; (b) side view.

Figure 5

Electronic density of states. (a) SWCN system; (b) slab system; (c) $\mathrm{SWCN}+\text{slab}$ system.