MECHANICAL DEFORMATION OF CARBON NANOTUBES FOLLOWED BY LOCAL ELECTRON TRANSFER

Abstract

Structure and geometry, modeling of carbon nanotubes enable to generate whole system from a single representative atom, by symmetry transformation. Hence, symmetry can be used to reduce calculations and prediction of electronics and wide range other relevant physical properties. Homogeneous mechanical deformation, that preserves symmetry, causes Hamiltonian reparameterization that influences change of energy bands change. For semiconducting carbon nanotubes, the most significant changes occur around Fermi level, where the process involves conducting and valence bands with the same angular quantum number. Deformations can be varied until bands come close to each other. Inside Brillouin zone bands approach always in two points symmetrical with respect to gamma point during homogeneous deformation of carbon nanotube. In accordance with the non-crossing rule, valence and conducted states never intersect if they have all quantum numbers the same, even in the moment they take cone-like shape when it comes to the change of Berry phase. This is interpreted as the change of average positions of two electrons simultaneously by tunneling from the onsite position toward the intermediate position between two neighbor sites or vice versa, despite that nanotube is semiconductor.