Superlattice Properties of Helical Nanostructures in a Transverse Electric Field

A charge carrier confined in a quasi-one-dimensional helical nanostructure in the presence of an electric field normal to the axis of the helix is subjected to a periodic potential proportional to the strength of the field and the helix radius. As a result, the behavior of this carrier is similar to that in a semiconductor superlattice with parameters controlled by the applied field. This behavior includes Bragg scattering of the charge carrier by a periodic potential, which results in an energy gap opening at the edge of the superlattice Brillouin zone. A certain type of carbon nanotube is shown to possess similar superlattice properties. Modification of the band structure is found to be significant for experimentally attainable electric fields, which raises the possibility of applying this effect to novel nanoelectronic devices.