Resonant photo-absorption and vibration spectroscopy were combined with scanning tunnelling microscopy in order to identify unambiguously the presence of Stone-Wales defects in C nanotubes. Based upon extensive time-dependent ab initio density functional calculations, resonant photo-excitation of Stone-Wales defects in the infra-red and ultra-violet regimes was proposed as a means for their identification. The onset of non-radiative decay to a local defect vibration, with a frequency of 1962/cm, served as a fingerprint of such defects. The bias dependence of the scanning tunnelling microscopic images revealed distinct features that were associated with the presence of Stone-Wales defects.

Spectroscopic Characterization of Stone-Wales Defects in Nanotubes. Y.Miyamoto, A.Rubio, S.Berber, M.Yoon, D.Tománek: Physical Review B, 2004, 69[12], 121413 (4pp)