ZA-derived phonons in the Raman spectra of single-walled carbon nanotubes

Vierck, Asmus; Gannott, Florentina; Schweiger, Manuel; Zaumseil, Jana; Maultzsch, Janina

doi:10.1016/j.carbon.2017.02.101

Cited by 19 publications

(43 citation statements)

References 35 publications

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“…Although the D-mode frequency was expected to vary systematically with diameter based on previous reports, , the range over which the D-mode varied was less than 12 cm –1 wide; therefore, the variation of this mode was not as significant as that of the IFM. This difference is clearly because the D-mode is associated with the optical phonon mode of graphene, while the IFM originates from an acoustic-like phonon mode. , …”

Section: Results and Discussionmentioning

confidence: 96%

“…In addition to the RBM and the G – -mode, SWCNTs generate an additional and less intense Raman peak that is often referred to as the intermediate frequency mode (IFM) in the frequency range from 300 to 1000 cm –1 . These peaks have been investigated using ensemble samples. − In addition, reports regarding minor Raman peaks generated by individual SWCNTs on a substrate have been published. , These prior papers emphasized the importance of employing isolated SWCNTs to demonstrate the chirality effects. In fact, SWCNTs having atomically thin tubular structures have been shown to interact significantly with their environment. − Therefore, the intrinsic properties of these structures can best be determined by examining individually suspended SWCNTs rather than ensemble samples.…”

Section: Introductionmentioning

confidence: 99%

“…4−9 In addition, reports regarding minor Raman peaks generated by individual SWCNTs on a substrate have been published. 10,11 These prior papers emphasized the importance of employing isolated SWCNTs to demonstrate the chirality effects. In fact, SWCNTs having atomically thin tubular structures have been shown to interact significantly with their environment.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Chirality and Defect Density on the Intermediate Frequency Raman Modes of Individually Suspended Single-Walled Carbon Nanotubes

et al. 2018

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The intermediate frequency Raman mode (IFM) in the range from 300 to 500 cm −1 of individually suspended single-walled carbon nanotubes (SWCNTs) was assessed to determine the effects of chirality and defect density. Photoluminescence spectroscopy was employed to confirm isolation and chirality of the SWCNTs. The IFM frequency exhibited a positive correlation with the nanotube diameter, as expected from prior studies. Raman and photoluminescence measurements were conducted simultaneously with the introduction of defects into a SWCNT. The photoluminescence intensity showed the largest reduction rate among all optical peaks analyzed. Furthermore, the intensity of the IFM increased with defect creation and showed almost the same behavior as the D-mode intensity. These results can be explained by the increase of the exciton−phonon coupling in the defective SWCNTs. Unambiguous chirality assignment using photoluminescence spectroscopy, along with employment of individually suspended samples that minimize environmental effects, enabled us to investigate the intrinsic nature of the IFM.

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Section: Results and Discussionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effects of Chirality and Defect Density on the Intermediate Frequency Raman Modes of Individually Suspended Single-Walled Carbon Nanotubes

et al. 2018

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“…Thus, we can conclude that even in the case of a pure 2D material such as graphene, the PNF signal does not depend on the polarization of the incoming light (Figure c). In order to explore the general validity of this observation beyond a particular material or geometry, we carried out the same experiment with polarized light on single-walled CNTs (Figure d,f), which are aligned along a defined direction and transferred on SiO 2 , as described in refs and . The signal intensity of the Raman G mode in the CNT is maximized for incoming light polarized parallel to the CNT and 0 for light polarized perpendicular to the tube .…”

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confidence: 96%

Breakdown of Far-Field Raman Selection Rules by Light–Plasmon Coupling Demonstrated by Tip-Enhanced Raman Scattering

Poliani

Wagner

Vierck

et al. 2017

J. Phys. Chem. Lett.

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We present an experimental study on the near-field light-matter interaction by tip-enhanced Raman scattering (TERS) with polarized light in three different materials: germanium-doped gallium nitride (GaN), graphene, and carbon nanotubes. We investigate the dependence of the TERS signal on the incoming light polarization and on the sample carrier concentration, as well as the Raman selection rules in the near-field. We explain the experimental data with a tentative quantum mechanical interpretation, which takes into account the role of plasmon polaritons, and the associated evanescent field. The driving force for the breakdown of the classical Raman selection rules in TERS is caused by photon tunneling through the perturbation of the evanescent field, with the consequent polariton annihilation. Predictions based on this quantum mechanical approach are in good agreement with the experimental data, which are shown to be independent of incoming light polarization, leading to new Raman selection rules for TERS.

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“…Recently, a step towards the understanding of the defectinduced D mode in nanotubes vs diameter and energy has been made using the hexagonal symmetry of graphene and geometrical considerations. 12,13 This approach allows assigning the two-phonon bands to pairs of definite phonons. However, the two-phonon band shape can only be predicted, taking into account the couplings and the electronic linewidth, and carrying out full integration over the Brillouin zone.…”

Section: Introductionmentioning

confidence: 99%

Two-phonon Raman bands of single-walled carbon nanotubes: A case study

Popov

2018

Phys. Rev. B

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It has been long accepted that the second-order Raman bands in carbon nanotubes are enhanced through the double-resonance mechanism. Although separate aspects of this mechanism have been studied for a few second-order Raman bands, including the most intense defect-induced D band and the two-phonon 2D band, a complete computational approach to the second-order bands is still lacking. Here, we propose such an approach, entirely based on a symmetry-adapted non-orthogonal tight-binding model with ab-initio-derived parameters. As a case study, we consider nanotube (6, 5), for which we calculate the two-phonon spectrum. We investigate in detail the 2D band and identify three contributions to it: a non-dispersive one and two dispersive ones, which are found to depend on the electron and phonon dispersion of the nanotube, and on the laser excitation. We also predict two-phonon bands, which are not allowed in the parent structure graphene. The obtained two-phonon bands are in very good agreement with the available experimental data. The symmetry-adapted formalism makes feasible the calculation of the two-phonon Raman bands of any observable nanotube.

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ZA-derived phonons in the Raman spectra of single-walled carbon nanotubes

Cited by 19 publications

References 35 publications

Effects of Chirality and Defect Density on the Intermediate Frequency Raman Modes of Individually Suspended Single-Walled Carbon Nanotubes

Effects of Chirality and Defect Density on the Intermediate Frequency Raman Modes of Individually Suspended Single-Walled Carbon Nanotubes

Breakdown of Far-Field Raman Selection Rules by Light–Plasmon Coupling Demonstrated by Tip-Enhanced Raman Scattering

Two-phonon Raman bands of single-walled carbon nanotubes: A case study

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