Electronic Properties of Carbon Nanotubes under an Electric Field

We study the electronic properties of carbon nanotubes under an electric field by investigating their electrostatic potentials, total energies, and energy gaps under a parallel electric field, based on the density functional theory. We find that, in capped carbon nanotubes, screening against the external electric field strongly depends on local atomic arrangement due to the inhomogeneous charge distribution arising from its bond alternation. In the case of armchair nanotubes, we find that the total energy and energy gap between the highest occupied and the lowest unoccupied states oscillate in triple periodicity of carbon nanotubes. (C) 2012 The Japan Society of Applied Physics