Nonlinear effect in conductance of a finite-length armchair single-wall carbon nanotube due to presence of a single impurity

Abstract

We have theoretically investigated the first correction to quantum conductance of finite Single-Wall Carbon Nanotubes (SWCNT) due to presence of a single impurity. We have tried to analytically obtain the change in the conductance of a SWCNT, by means of a perturbative scheme along with finite-length real space nearest neighbors tight binding method for carbon π-orbitals. Dependence of the differential conductance on source-drain voltage as well as its sensitive dependence on the position of the possible impurity/defect on the tube is studied. Results suggest a promising method for spectroscopy of electronic energy levels and imaging accurate position of carbon atoms in a SWCNT. © 2008 IOP Publishing Ltd.