We solve the Green's equation exactly for the armchair-type carbon nanotube
s with one pi-electron tight-binding Hamiltonian and obtain analytic expres
sions for the conductance of the nanotube with local perturbations. Our res
ults explicitly show the dependence of the conductance on the Fermi level,
the tubular radius, and the strength of the perturbation. (C) 1999 Elsevier
Science Ltd. All rights reserved.