Long-range resonant effects on electronic transport of nitrogen-doped carbon nanotubes

The electronic transport properties of ordered and disordered nitrogen-doped metallic carbon nanotubes with long-range correlation are studied numerically with a tight-binding model. Doping with both translational (axial) and screw symmetry are considered. In periodic defective systems, when axial doping is considered, two classes of electronic transport responses are obtained. One quantum conductance plateau settles down around the defect energy only when the period of the structure is a multiple of the Fermi wavelength 3d0 (d0 being the period of the perfect armchair host nanotube), because the Bloch-like propagating modes survive. Otherwise, a conduction gap is predicted. For the screw doping configuration, the same resonant electronic transport is observed when the rotational angle fulfills one of the rotational symmetries of the perfect nanotube. Furthermore, for disordered systems, the conventional Anderson localization is partially prohibited around the defect energy for particular axial and circular random doping configurations. These conclusions are valid for both armchair and chiral metallic nanotubes and should remain true for other modifications of the nanotube by covalent or noncovalent doping.