Abstract Submitted to the    NANOTUBE'04 Conference:

The tangential G-band feature in the Raman spectra of metallic single-wall carbon nanotube shows two peaks: a higher frequency component having the Lorentzian shape and a lower-frequency component of lower intensity with a Breit-Wigner–Fano (BWF) lineshape [1]. This interesting feature has been analyzed on the basis of phonon-plasmon coupling in a metallic nanotube. It is shown that while the gapless semi-acoustic plasmon cannot account for the observed spectra as claimed by Kempa [2], the low-lying optical plasmon corresponding to the tangential motion of the electrons on the nanotube surface [3] can explain the observed features associated with both the high- and low-frequency components. In particular, this theory gives both the Lorentzian and BWF lineshapes. Furthermore, this theory shows that the BWF peak moves to higher frequency, has lower intensity and lower half width at larger diameters. All these features are in agreement with experimental observations.

1. S.D.M. Brown et al., Phys. Rev. B 63, 155414 (2001).
2. K. Kempa, Phys. Rev. B 66, 195406 (2002).
3. P. Longe and S.M. Bose, Phys. Rev. B 48, 18239 (1993).