Spontaneous twisting and shrinking of carbon nanotubes
  Deformations of single-wall carbon nanotubes are investigated within the tight-binding model with deformation-dependent hopping energies. We show that the nanotubes tend to twist and shrink spontaneously at zero temperature. The explicit values of the deformation parameters are computed for a wide range of nanotubes with varying diameter and chirality. The changes of the spectral gap associated with the spontaneous deformation are shown to depend on the chirality of the nanotubes. 
V\'it Jakubsk\'y and Axel P\'erez-Obiol
cond-mat.mes-hall