Chapter 2 - Metallic Carbon Nanotubes for Current Transport

Abstract

The unique band structure of metallic carbon nanotubes, which is partly responsible for their superb current carrying capacity, differs from the electronic band structure of conventional metals. The band structure shows various subbands arising from quantization of the wave vector around the circumference of the nanotube. The total transmission at a given electron energy is equal to the electron transmission probability times the number of channels, and for perfect transmission without scattering (i.e. transmission probability equal to 1), it is simply equal to the number of channels. Thus, the total transmission shows the steps when a subband opens or closes. The magnitude of the change in a transmission at these steps corresponds to the subband degeneracy. The total number of subbands increases with increasing nanotube diameter because the number of quantum numbers arising from quantization of the electron wavefunction around the nanotube circumference becomes larger. From a basic Physics perspective, metallic nanotubes have been of immense interest to researchers studying electron–electron interactions in condensed matter systems because they exhibit the Physics of Luttinger liquid behavior.