Analysis of quantum conductance of carbon nanotube junctions by the effective-mass approximation

Abstract

The electron transport through the nanotube junctions that connect different metallic nanotubes by a pair consisting of a pentagonal defect and a heptagonal defect is investigated with Landauer’s formula and the effective-mass approximation. From our previous calculations based on the tight-binding model, it is known that the conductance is determined almost only by two parameters, i.e., the energy units of the onset energy of more than two channels and the ratio of the radii of the two nanotubes. The conductance is calculated again with effective-mass theory in this paper and a simple analytical form of the conductance is obtained by considering special boundary conditions of the envelope wave functions. The two scaling parameters appear naturally in this treatment. The results obtained by this formula coincide fairly well with those of the tight-binding model. The physical origin of the scaling law is clarified by this approach.