Characteristic vibrational modes of a single vacancy in a zigzag carbon nanotube

Abstract

We have applied ab initio calculations to studying phonon frequencies and the corresponding eigenmodes for zigzag carbon nanotubes with single vacancies. We find two types of vibrational modes that serve as fingerprints of the single vacancy, which may be detected by Raman spectra technique. Our calculations reveal that these vibrational frequencies exhibit a weak size dependence on the diameters of tubes. Moreover, it is found that the frequencies of radial breathing modes of the defective tubes are quite close to those of the related perfect ones.