Experimental evidence of a mechanical coupling between layers in an individual double-walled carbon nanotube.
We perform transmission electron microscopy, electron diffraction, and Raman scattering experiments on an individual suspended double-walled carbon nanotube (DWCNT). The first two techniques allow the unambiguous determination of the DWCNT structure: (12,8)@(16,14). However, the low-frequency features in the Raman spectra cannot be connected to the derived layer diameters d by means of the 1/d power law, widely used for the diameter dependence of the radial-breathing mode of single-walled nanotubes. We discuss this disagreement in terms of mechanical coupling between the layers of the DWCNT, which results in collective vibrational modes. Theoretical predictions for the breathing-like modes of the DWCNT, originating from the radial-breathing modes of the layers, are in a very good agreement with the observed Raman spectra. Moreover, the mechanical coupling qualitatively explains the observation of Raman lines of breathing-like modes, whenever only one of the layers is in resonance with the laser energy.
Université Montpellier 2, Laboratoire Charles Coulomb UMR 5221, F-34095 Montpellier, France.
D
D
Levshov
T X
TX
Than
R
R
Arenal
V N
VN
Popov
R
R
Parret
M
M
Paillet
V
V
Jourdain
A A
AA
Zahab
T
T
Michel
Yu I
YI
Yuzyuk
J-L
JL
Sauvajol
D000268:Adhesiveness; D008422:Materials Testing; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D013314:Stress, Mechanical; D013718:Tensile Strength