Softening of the radial breathing mode in metallic carbon nanotubes.
The softening of the radial breathing mode (RBM) of metallic single walled carbon nanotubes (m-SWNTs) due to electron-phonon coupling has been studied by observing the Fermi level [see text] dependence of the RBM Raman peak. In situ Raman spectra were obtained from several individual m-SWNTs while varying [see text] electrochemically. The RBM frequency of an intrinsic m-SWNT is shown to be down-shifted relative to highly doped tubes by approximately 2 cm(1). The down-shift is greatest for small diameter and small chiral angle SWNTs. Most tubes show no change in RBM linewidth. A comparison is drawn between the RBM and the G band (A(LO) phonon) with respect to the [see text] dependence of their frequencies and linewidths.
Farhat
H
H
Department of Materials Science and Engineering, MIT, Cambridge Massachusetts 02139, USA.
Sasaki
K
K
Kalbac
M
M
Hofmann
M
M
Saito
R
R
Dresselhaus
M S
MS
Kong
J
J
D055664:Electrochemical Techniques; D018020:Lithium Compounds / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry*; D037742:Nanotubes, Carbon / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry; D013059:Spectrum Analysis, Raman / Q000379:methods
D018020:Lithium Compounds; D037742:Nanotubes, Carbon; D011092:Polyethylene Glycols