Conductance modulation of metallic carbon nanotubes by remote charged rings

We calculate the effects of a longitudinal electrostatic perturbation on a metallic single-wall carbon nanotube and demonstrate conductance modulation. Such external modulation would be completely screened in bulk 3D metals but is possible in SWNTs because their electrons are quasi-two-dimensional and can interact with a nearby system of charges. The resultant modulation of the conductance is determined by the strength of the self-consistent potential and its periodicity over shorter or longer distances. We employ the zero-temperature single-particle Green's function transport approach in the empirical tight-binding approximation to quantify the modulation of conductance and also consider the limit of a superlattice.