Modification of the electronic structure in a carbon nanotube with the charge dopant encapsulation

We present the first-principles study of effects of the charge dopants such as cesium and iodine encapsulated on the electronic structure of carbon nanotubes (CNTs). An encapsulated cesium atom donates an electron to the nanotube and produces donorlike states below the conduction bands. In contrast, an iodine trimer (I-3) accepts an electron from the nanotube and produces an acceptor-like state above the valence band maximum. We find that a Cs atom inside a metallic armchair CNT gives rise to spatial oscillations of the density of states near the Fermi level. (C) 2008 American Institute of Physics.