Probing the single-wall carbon nanotube bundle: Raman scattering under high pressure

Venkateswaran, U. D.; Rao, Apparao M.; Richter, Ernst; Menon, Madhu; Rinzler, Andrew G.; Smalley, R. E.; Eklund, P. C.

doi:10.1103/physrevb.59.10928

Cited by 401 publications

(486 citation statements)

References 22 publications

Supporting

Mentioning

435

Contrasting

Order By: Relevance

“…Since then, the radial deformations of the carbon nanotubes in bundles and crystals have been investigated both experimentally and theoretically by many authors. 15,16,[21][22][23][24][25][26][27][28][29] These studies on bundles of SWNTs with particular diameters of ϳ1.4 nm have suggested a pressureinduced phase transformation from circular to either hexagonal or flattened tubes at 1.4-2.1 GPa. 15,[21][22][23][24][25] This shape transition has been indirectly evidenced by the disappearance of symmetric radial breathing modes in Raman spectra.…”

Section: Introductionmentioning

confidence: 99%

“…15,16,[21][22][23][24][25][26][27][28][29] These studies on bundles of SWNTs with particular diameters of ϳ1.4 nm have suggested a pressureinduced phase transformation from circular to either hexagonal or flattened tubes at 1.4-2.1 GPa. 15,[21][22][23][24][25] This shape transition has been indirectly evidenced by the disappearance of symmetric radial breathing modes in Raman spectra. 21,22 The shape transition has also been directly observed in the diffraction experiments, by either x-ray 15,16 or neutron, 27 although there remains inconsistency in these experimental results.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Radial deformation and stability of single-wall carbon nanotubes under hydrostatic pressure

Hasegawa

Nishidate

2006

Phys. Rev. B

View full text Add to dashboard Cite

In this paper we have developed a theory of energetics for isolated single-wall carbon nanotubes ͑SWNTs͒ deformed in the radial direction, and applied this theory to investigate their deformation characteristics and stability under hydrostatic pressure. The starting point of the theory is the strain energy of SWNTs predicted by ab initio calculations based on the density functional theory ͑DFT͒, which shows the same behavior as that obtained for the continuum elastic shell model. We extend this result for inflated SWNTs with circular cross section to calculate the deformation energy of a deformed SWNT without performing further DFT calculations. This extension is then complemented by a van der Waals interaction, which is not fully taken into account in the DFT approximations currently in use but becomes important in highly deformed tubes. We find that the minimum pressure, P 1 , for the radial deformation to occur is proportional to the inverse cube of tube diameter, D, in agreement with the recent theoretical predictions as well as the classical theory of buckling. The radial deformation of SWNTs with D Ͻ 2.5 nm is found to be elastic up to very high pressure and they hardly collapse. On the other hand, SWNTs with D Ͼ 2.5 nm show a plastic deformation and collapse if the applied hydrostatic pressure exceeds a critical value, which is about 30-40% higher than P 1 and also varies as D −3 though approximately. These SWNTs with large D collapse when the cross-sectional area is about 60% reduced with respect to the circular one. It is also found that for SWNTs with D Ͼ 7.0 nm, the plastically deformed ͑collapsed͒ state is more stable than the inflated one. This critical value of D is somewhat larger than previously predicted.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Radial deformation and stability of single-wall carbon nanotubes under hydrostatic pressure

Hasegawa

Nishidate

2006

Phys. Rev. B

View full text Add to dashboard Cite

show abstract

“…Figure 2 also shows the local environment of the carbon atoms involved in the interbonding of the nanotubes for (6,0) and (7,0). In the first case, the covalent bonding occurs between carbon atoms on two hexagonal rings (Fig.…”

mentioning

confidence: 99%

“…The intertube interactions in nanoropes can be probed by applying external pressure to vary the intertube distance [6][7][8] . For fullerenes, such high pressure studies have yielded many interesting results including new compounds such as the pressure-induced polymeric phases of C 60 9 .…”

mentioning

confidence: 99%

Pressure-induced interlinking of carbon nanotubes

et al. 2000

View full text Add to dashboard Cite

We predict new forms of carbon consisting of one and two dimensional networks of interlinked single wall carbon nanotubes, some of which are energetically more stable than van der Waals packing of the nanotubes on a hexagonal lattice. These interlinked nanotubes are further transformed with higher applied external pressures to more dense and complicated stable structures, in which curvature-induced carbon sp 3 re-hybridizations are formed. We also discuss the energetics of the bond formation between nanotubes and the electronic properties of these predicted novel structures.PACS numbers: 61.48.+c,61.46.+w,62.50.+p,61.50.Ah,71.20.Tx Carbon nanotubes, originally discovered as by-products of fullerene synthesis 1,2 , are now considered to be the building blocks of future nanoscale electronic and mechanical devices. It is therefore desirable to have a good understanding of their electronic and mechanical properties and the interrelations between them. In particular, single wall carbon nanotubes (SWNT) provide a system where the electronic properties can be controlled by the structure of the nanotubes and by various deformations of their geometries 3-5 . The physical properties can also be altered by intertube interactions between nanotubes packed in hexagonal lattices, as so called "nanoropes".The intertube interactions in nanoropes can be probed by applying external pressure to vary the intertube distance 6-8 . For fullerenes, such high pressure studies have yielded many interesting results including new compounds such as the pressure-induced polymeric phases of C 60 9 . It is, therefore, of interest to inquire if similar covalent-bonding can occur between the nanotubes in a rope. This could have important consequences for nanoscale device applications and composite materials which require strong mechanical properties since nanoropes consisting of inter-linked SWNT will be significantly stronger than nanoropes composed of van der Waals packed nanotubes 10 .A recent Raman study on SWNT ropes carried out up to 25.9 GPa 7 showed that the mode intensities and energies are not completely reversible upon pressure cycling, suggesting irreversible pressure-induced changes in the structure. In another high pressure study Chesnokov et al. 8 observed a very large volume reduction and high compressibility, signaling the presence of a microscopic volume-reducing deformation other than van der Waals compression. Some of these pressure-induced effects are tentatively attributed to possible crushing or flattening the nanotube cross section from circular to elliptical or hexagonal 8 . Motivated by these reports, we investigated possible new pressureinduced ground state structures for (n,0) nanotube ropes 11 from first-principles total energy calculations using the pseudopotential method within the generalized gradient approximation (GGA) 12 . We observed an elliptical distortion of the nanotubes under pressure and subsequent curvature-induced carbon re-hybridization, giving rise to one or two dimensional interlinked networks of ...

show abstract

“…10,11 The methanol-ethanol medium is used in several high pressure studies on CNTs. 6,[12][13][14][15][16][17] Argon gas adsorption studies on CNTs 18 identified several adsorption sites: interstitial channels, external groove sites, and the external surface. Pseudohexagonal medium range ordering of adsorbents have been predicted on the external surface of CNTs.…”

mentioning

confidence: 99%