Electron Configuration of Carbon Nanotubes

In the paper the analysis of electron band structure of infinite carbon nanotubes was performed using Green's function method. The electron dispersion law was found in harmonic and nearest neighbor approximation. One can see that carbon nanotubes of infinite length can be divided into two classes: metallic and semiconducting. Additional spatial confinement of the system along the nanotube axes leads to the opening of the forbidden gap even in nanotubes that are metallic for infinite length. The value of the forbidden gap decreases by increasing the tube length. The dependence of the forbidden gap on the tube length is not monotonic; it has oscillatory character for short tubes.