Oscillations of local density of states in defective carbon nanotubes

Abstract

We have made a numerical calculation on the spatial oscillation of the local density of states (LDOS) for a single walled carbon nanotube with a Stone-Wale defect, which induces some localized defect states, decaying rapidly away from the defect. More importantly, it is found that even far from the defect region, there still exist some small regular LDOS oscillations due to the quantum interference, which become much intensified, especially, when the energy slightly exceeds a van Hove singularity. All the oscillations can be classified into two types, depending on the geometrical symmetry of the defective tube, and can be qualitatively explained by the quantum scattering theory of a quasi-one-dimensional system. The LDOS oscillation in energy at a given position far from the defect is also found, whose period becomes shorter and shorter when the position goes away from the defect farther and farther.