Resonant Raman Spectroscopy of Armchair Carbon Nanotubes: Absence of 'Metallic' Signature

Autor: Haroz, E. H., Duque, J. G., Rice, W. D., Densmore, C. G., Kono, J., Doorn, S. K.
Rok vydání: 2011
Předmět:
Zdroj: Physical Review B 84, 121403(R) (2011)
Druh dokumentu: Working Paper
DOI: 10.1103/PhysRevB.84.121403
Popis: The appearance of a broad peak at $\sim$1550 cm$^{-1}$ (G$^{-}$ peak) in carbon nanotube resonant Raman scattering spectra has been conventionally attributed to the presence of metallic nanotubes. Here, we present resonant Raman measurements on macroscopic nanotube ensembles enriched in armchair species prepared through density gradient ultracentrifugation. Our data clearly demonstrate that the broad G$^{-}$ mode is absent for armchair structures and appears only when the excitation laser is resonant with non-armchair "metals." Due to the large number ($\sim$10$^{10}$) of nanotubes across several armchair species probed, our work firmly establishes a general correlation between G-band lineshape and nanotube structure.
Comment: 4 pages, 4 figures
Databáze: arXiv