TITLE:
Theory of Conductivity in Semiconducting Single-Wall Carbon Nanotubes
AUTHORS:
Shigeji Fujita, Salvador Godoy, Akira Suzuki
KEYWORDS:
Semiconducting SWNT; Cartesian Unit Cell Model; Cooper Pair; Bloch Electron Dynamics
JOURNAL NAME:
Journal of Modern Physics,
Vol.3 No.10,
October
31,
2012
ABSTRACT: The conduction of a single-wall carbon nanotube depends on the pitch. If there are an integral number of carbon hexagons per pitch, then the system is periodic along the tube axis and allows “holes” (not “electrons”) to move inside the tube. This case accounts for a semiconducting behavior with the activation energy of the order of around 3 meV. There is a distribution of the activation energy since the pitch and the circumference can vary. Otherwise nanotubes show metallic behaviors (significantly higher conductivity). “Electrons” and “holes” can move in the graphene wall (two dimensions). The conduction in the wall is the same as in graphene if the finiteness of the circumference is disregarded. Cooper pairs formed by the phonon exchange attraction moving in the wall is shown to generate a temperature-independent conduction at low temperature (3 - 20 K).