Band-gap change of carbon nanotubes: Effect of small uniaxial and torsional strain

Yang, Liu; Anantram, M. P.; Han, Jie; Lu, Jianping

doi:10.1103/physrevb.60.13874

Cited by 394 publications

(343 citation statements)

References 16 publications

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“…To date, several experiments have probed the electrical 5-9 and mechanical 10-13 properties. However, there have been fewer (and less controlled) efforts examining the effect of mechanical strain on the electrical properties 8 , despite considerable theoretical effort to predict the effect of strain and various defects [14][15][16][17][18] . We present the results of our experiments using the probe of an Atomic Force Microscope (AFM) to apply a mechanical stress to multi-walled carbon nanotubes (MWNT), while monitoring the resistance in situ.…”

mentioning

confidence: 99%

In situ resistance measurements of strained carbon nanotubes

Paulson

Falvo

Snider

et al. 1999

Applied Physics Letters

139

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We investigate the response of multi-walled carbon nanotubes to mechanical strain applied with an Atomic Force Microscope (AFM) probe. We find that in some samples, changes in the contact resistance dominate the measured resistance change. In others, strain large enough to fracture the tube can be applied without a significant change in the contact resistance. In this case we observe that enough force is applied to break the tube without any change in resistance until the tube fails. We have also manipulated the ends of the broken tube back in contact with each other, re-establishing a finite resistance. We observe that in this broken configuration the resistance of the sample is tunable to values 15-350 kΩ greater than prior to breaking. Soon after their discovery by Iijima, carbon nanotubes 1 (CNTs) were predicted to have interesting electrical

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mentioning

confidence: 99%

In situ resistance measurements of strained carbon nanotubes

Paulson

Falvo

Snider

et al. 1999

Applied Physics Letters

139

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“…TB calculations [36] provide the electronic band structure (figure 4), namely the fundamental bandgap E g = E µ,µ = 1.321 eV, corresponding to a wavelength λ = 939 nm, nanotube diameter d = 0.611 nm and chiral angle θ = 26.33 • . The resonant transition energy for circularly polarized excitations is E µ,µ±1 = 1.982 eV, corresponding to a resonant wavelength λ 0 = 626.5 nm.…”

Section: Theoretical Framework For Description Of the Natural Opticalmentioning

confidence: 99%

Nonlinear coherent magneto-optical response of a single chiral carbon nanotube

Slavcheva

Roussignol

2010

New J. Phys.

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View the article online for updates and enhancements. Abstract. We propose a theoretical framework and dynamical model for the description of the natural optical activity and Faraday rotation in an individual chiral single-wall carbon nanotube (CNT) in the highly nonlinear coherent regime. The model is based on a discrete-level representation of the optically active states near the band edge. Chirality is modelled by a system Hamiltonian in a four-level basis corresponding to energy-level configurations, specific for each handedness, that are mirror reflections of each other. The axial magnetic field is introduced through the Aharonov-Bohm and Zeeman energylevel shifts. The time evolution of the quantum system, describing a single nanotube with defined chirality, under an ultrashort polarized pulse excitation is studied using the coupled coherent vector Maxwell-pseudospin equations (Slavcheva 2008 Phys. Rev. B 77 115347). We provide an estimate for the effective dielectric constant and the optical dipole matrix element for transitions excited by circularly polarized light in a single nanotube and calculate the magnitude of the circular dichroism and the specific rotatory power in the absence and in the presence of an axial magnetic field. Giant natural gyrotropy (polarization rotatory power ∼3000 • mm −1 (B = 0 T)), superior to that of the crystal birefringent materials, liquid crystals and comparable or exceeding that of the artificially made helical photonic structures, is numerically demonstrated for the specific case of a (5, 4) nanotube. A quantitative estimate of the coherent nonlinear magneto-chiral optical effect in an axial magnetic field is given 3 Authors to whom any correspondence should be addressed. . The model provides a framework for the investigation of the chirality and magnetic field dependence of the ultrafast nonlinear optical response of a single CNT.

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“…Theoretical studies of strained CNT find that the band gap will oscillate between zero and nonzero values as the strain is increased, in agreement with the experimental results. [13][14][15][16][17][18][19] However, most of these theoretical studies tend to assume that the CNT lattice vectors distort like solid object vectors. Here, as an example of how to apply our general rule for metallic CNT, we consider a CNT under small axial and torsional strains, where small implies that the applied strains are not sufficient to cause buckling or kinking, 20,21 while taking into account the fact that lattices do not distort like solid objects.…”

Section: Introductionmentioning

confidence: 99%

Electronic properties of carbon nanotubes with distinct bond lengths

Bunder

Hill

2010

Journal of Applied Physics

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In band structure calculations commonly used to derive the electronic properties of carbon nanotubes it is generally assumed that all bond lengths are equal. However, hexagonal carbon lattices are often irregular and may contain as many as three distinct bond lengths. A regular $(n,m)$ carbon nanotube will be metallic if p=(n-m)/3 for integer p. Here we analytically derive the generalized condition for metallic irregular carbon nanotubes. This condition is particularly relevant to small radius nanotubes and nanotubes experiencing small applied strains. In band structure calculations commonly used to derive the electronic properties of carbon nanotubes, it is generally assumed that all bond lengths are equal. However, hexagonal carbon lattices are often irregular and may contain as many as three distinct bond lengths. A regular ͑n , m͒ carbon nanotube will be metallic if p = ͑n − m͒ / 3 for integer p. Here we analytically derive the generalized condition for metallic irregular carbon nanotubes. This condition is particularly relevant to small radius nanotubes and nanotubes experiencing small applied strains.

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Band-gap change of carbon nanotubes: Effect of small uniaxial and torsional strain

Cited by 394 publications

References 16 publications

In situ resistance measurements of strained carbon nanotubes

In situ resistance measurements of strained carbon nanotubes

Nonlinear coherent magneto-optical response of a single chiral carbon nanotube

Electronic properties of carbon nanotubes with distinct bond lengths

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