Band-gap modification of defective carbon nanotubes under a transverse electric field

Ab initio calculations show that the band-gap modulation of semiconducting carbon nanotubes with mono-vacancy defect can be easily achieved by applying a transverse electric field. We found that the band structures of the defective carbon nanotubes vary quite differently from that of the perfect nanotube, and strongly depend on the applied direction of the transverse electric field. A mechanism is proposed to explain the variation of the band gap, and potential applications of these phenomena are discussed.