First-principles study of current–voltage characteristics of two-terminal carbon nanostructures

We present the first-principles investigation of the transport properties of nanotubes connected to metal electrodes under external bias potential. We have developed the technique to calculate the current–voltage (I–V) curves by using the local-density approximation in the density-functional theory. We apply this technique to Al-nanotube-Al systems with different contact geometries regarding the position, the orientation, and the distance of nanotube to the electrode. These different geometries at contact can play an important role in the transport properties. The I–V curves have the different behaviors although the nanotube is connected to the same electrode. The transmission rate from one electrode to the other electrode shows strong dependence on the contact geometry.