Suppression of the pseudoantisymmetry channel in the conductance of telescoped double-wall nanotubes

The conductance of telescoped double-wall nanotubes (TDWNTs) composed of two armchair nanotubes [(nO,nO) and (nO-5,nO-5) with nO10] is calculated using the Landauer formula and a tight binding model. The results are in good agreement with the conductance calculated analytically by replacing each single-wall nanotube with a ladder, as expressed by (2e²∕h)(T₊+T_-), where T₊0.2em0ex(T_-) is the transmission rate of the pseudosymmetry (pseudoantisymmetry) channel. Interlayer hopping of the - channel in the ladder model explains two key results: the low value of T_- for TDWNTs except when nO=10, and the particularly low value of T_- when either nO or nO-5 is a multiple of three. In the latter case, T_- becomes zero when the saturation of the number of interlayer bonds per atom is neglected.