<i>Ab initio</i>structural, elastic, and vibrational properties of carbon nanotubes

Sánchez‐Portal, Daniel; Artacho, Emilio; Soler, José M.; Rubio, Ángel; Ordejón, Pablo

doi:10.1103/physrevb.59.12678

Cited by 914 publications

(628 citation statements)

References 59 publications

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“…The E value of 0.25 TPa is remarkably high for a 2D membrane and approaches that predicted for pristine graphene. 25 At the same time, this value provides a boundary for the maximum mechanical performance that could be reached via optimization of the interlayer coupling within bulk, paper-like materials based on (reduced) GO. 14 From Figure 5a, it can be seen that the conductivity of the reduced GO sheets scales inversely with the elastic modulus.…”

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confidence: 99%

Elastic Properties of Chemically Derived Single Graphene Sheets

2008

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The elastic modulus of freely suspended graphene monolayers, obtained via chemical reduction of graphene oxide, was determined through tip-induced deformation experiments. Despite their defect content, the single sheets exhibit an extraordinary stiffness (E ) 0.25 TPa) approaching that of pristine graphene, as well as a high flexibility which enables them to bend easily in their elastic regime. Built-in tensions are found to be significantly lower compared to mechanically exfoliated graphene. The high resilience of the sheets is demonstrated by their unaltered electrical conductivity after multiple deformations. The electrical conductivity of the sheets scales inversely with the elastic modulus, pointing toward a 2-fold role of the oxygen bridges, that is, to impart a bond reinforcement while at the same time impeding the charge transport.Recent experiments have revealed the thermodynamic stability of graphene under ambient conditions, 1-3 which strongly revived the interest in the electrical and mechanical properties of this fascinating carbon nanostructure. Two major methods have been established for the fabrication of graphene monolayers, namely, mechanical exfoliation of graphite 2 and vacuum graphitization of silicon carbide. 3,4 More recently, chemical reduction of graphene oxide (GO) has been reported as an alternative, solution-based route, for obtaining graphenelike sheets which offers the advantages of being cheap and up-scalable. [5][6][7][8] Even though GO is a good insulator, deoxygenation has been shown to substantially enhance its electrical conductivity, albeit the obtained values of ∼1 S/cm remain 2-3 orders of magnitude below that of pristine graphene. 6,7 Due to the limited efficiency of the reduction process, the obtained sheets still contain residual oxygenated functional groups of the starting material. Microscopic studies of the reduced GO also indicate the coexistence of graphitic regions with defect clusters 6,9 in agreement with proposed models. [9][10][11] In addition to its interesting electrical characteristics, this 2D material is expected to have also unique mechanical properties. Recent studies have witnessed its suitability for the fabrication of composites 12,13 and paperlike materials 14 with excellent mechanical properties. However, in order to promote its application in nanotechnology, the mechanical characterization of single sheets is of upmost relevance.Here we present a study of the mechanical and electrical properties of suspended, chemically reduced GO single sheets. Graphite oxide prepared via Hummers method 15 was dispersed in water, deposited onto a Si/SiO 2 substrate, and subsequently reduced by hydrogen plasma treatment. The obtained samples exhibited a high yield of monolayers with lateral dimensions of 0.1-5 µm. Preselected layers were then contacted by standard e-beam lithography with Ti/Au electrodes. In order to freely suspend the layers (Figure 1), the samples were wet etched by buffered hydrofluoric acid, followed by critical point drying to prevent ...

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confidence: 99%

Elastic Properties of Chemically Derived Single Graphene Sheets

2008

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“…As a result, the 2-D graphene phonon modes are further split into a large number of sub-bands. If the SWCNT contains N atoms per unit cell, there are 3N phonon modes in total, many of which are degenerated [26]. As the simulated SWCNT consisted of 36 atoms, total 108 phonon modes were obtained.…”

Section: Vibrational Modesmentioning

confidence: 99%

“…The ab initio approach is advantageous because such calculations do not depend on any predefined parameter. There are different authors that have reported ab initio phonon dispersion of SWCNT's, all using the super cell approach [26][27][28].The largest differences between ab initio calculations and zone-folding occur in the low frequency range and for tubes with small diameters (less than 0.7 nm) also in the high frequency range.…”

Section: Introductionmentioning

confidence: 99%

Vibrational spectra and phonon dispersion analysis of a single-walled zigzag carbon nanotube: A first principles study

Sharma

Jaggi

2016

Can. J. Phys.

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This paper reports a vibrational spectroscopic study on a zigzag single-walled carbon nanotube (SWCNT) using the first-principles method based on density functional theory (DFT). The most suitable exchange correlation functional for DFT analysis was determined by comparing the predicted value of band gap of the SWCNT under study with the experimental value reported in the literature. General gradient approximation functional in combination with revised Perdew–Burke–Ernzerh sub-functional was found to give the best results. Using this optimum combination, phonon density of states and phonon dispersion curves have been determined. The analysis of results obtained focuses on symmetry considerations, group theory analysis, segregation of Raman active and infrared (IR) active vibrational modes and interpretation of the Raman and IR spectra obtained. The earlier approaches to the problem rely upon the zone folding technique and force constant models in which structural relaxation factor is not taken care of. An ab initio approach has been adopted by the authors in this work, which is advantageous as it neither depends on some predefined parameter nor does it ignore the structural relaxation factor. Analysis of the Raman spectrum reveals some additional peaks other than the commonly known radial breathing mode, D, G, and G′ bands in the SWCNT spectra, which have been recently reported to be observed experimentally also. Similarly, the theoretically developed IR spectrum for the simulated SWCNT is also in agreement with experimental observations. The methodology presented thus provides a very useful and novel simulation route to predict the vibrational modes, Raman spectra, and IR spectra of SWCNTs theoretically.

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“…Continuum elastic shell models [26][27][28][29][30][31] used to study RBM vibration of SWCNTs do not consider scale effects. Also, atomistic methods [32][33][34] which do consider scale effects are costly and time consuming to implement particularly for large-scale systems.…”

Section: Introductionmentioning

confidence: 99%

Analysis of radial breathing mode of vibration of single‐walled carbon nanotubes via doublet mechanics

Fatahi-Vajari

Imam

2016

Z Angew Math Mech

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This paper investigates the radial breathing mode (RBM) vibration of single-walled carbon nanotubes (SWCNTs) based on doublet mechanics (DM) with a length scale parameter. A second order partial differential equation that governs the RBM vibration of SWCNTs is derived. Using DM, the relation between natural frequency and length scale parameter is derived in the RBM mode of vibration. It is shown that the length scale parameter plays significant role in the RBM vibration response of SWCNTs. The length scale parameter decreases the natural frequency of vibration compared to the predictions of the classical continuum models. However, with increase in tube radius, the effect of the scale parameter on the natural frequency decreases. The results obtained herein are compared with the existing theoretical and experimental results and good agreement with the latter is observed.

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Ab initiostructural, elastic, and vibrational properties of carbon nanotubes

Cited by 914 publications

References 59 publications

Elastic Properties of Chemically Derived Single Graphene Sheets

Elastic Properties of Chemically Derived Single Graphene Sheets

Vibrational spectra and phonon dispersion analysis of a single-walled zigzag carbon nanotube: A first principles study

Analysis of radial breathing mode of vibration of single‐walled carbon nanotubes via doublet mechanics

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