Conductance modulation of metallic carbon nanotubes by remote charged ringsS. Barraza-Lopez1, S. V. Rotkin2, Y. Li1 and K. Hess1
1 Department of Physics and Beckman Institute for Advanced Science and Technology University of Illinois at Urbana-Champaign - 405 North Mathews Avenue Urbana, IL 61801, USA
2 Physics Department, Lehigh University - 16 East Memorial Drive Bethlehem, PA 18015, USA
received 22 October 2004; accepted in final form 17 January 2005
published online 16 February 2005
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.
73.63.Fg - Nanotubes.
71.30.+h - Metal-insulator transitions and other electronic transitions.
73.23.Ad - Ballistic transport.
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