Quantum interference in deformed carbon nanotube waveguides

Quantum interference in two types of deformed carbon nanotubes (CNTs)—i.e., axially stretched and atomic-force-microscope-tip-deformed CNTs—has been investigated by the $\pi$-electron-only and four-orbital tight-binding method. It is found that the rapid conductance oscillation period is very sensitive to the applied strains and decreases in an inverse proportion to the deformation degree, which could be used as a powerful experimental tool to detect precisely the deformation degree of the deformed CNTs. Also, the $\sigma \text{−}\pi$ coupling effect is found to be negligible under axially stretched strain, while it works on the transport properties of the tip-deformed CNTs.