Axial strain and twist-induced changes in the electronic structure of carbon nanotubes

Based on the tight-binding model of generalized honeycomb lattice on cylinder, the band structure changes induced by axial strain and twist are present for the signal-wall carbon nanotubes (SWCNTs). The deformation-modified hopping amplitudes are dominated by the metric tensor and the curvature tensor. The analytical relations of the energy bands and the band gaps to both armchair and zigzag tubes are obtained. For the chiral nanotubes, we have successfully investigated the deformation-induced changes in band structure of individual nanotubes of known chiral index. The results in our model, returning to the undeformed tubes, are in good agreement with the previous experiments and theories.