Electron/Electromagnetic Multiple Scattering and Localization

Dragoman, Daniela; Dragoman, Mircea

doi:10.1007/978-3-662-09647-5_3

Cited by 3 publications

(4 citation statements)

References 77 publications

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“…The unique position of the THz range, in the gap between the parts of electromagnetic spectrum, which are accessible by either electronic or optical devices, leads to an unprecedented diversity in approaches to bridging the gap. [1][2][3][4][5][6][7][8][9][10] One of the latest trends in THz technology is to employ carbon nanomaterials as building blocks of high-frequency devices. 11 In particular, there are a growing number of proposals using carbon nanotubes for THz applications including several schemes [12][13][14][15][16][17] put forward by some of the authors of the present work.…”

Section: Introductionmentioning

confidence: 99%

“…Within the frame of a simple zone-folding model of the π-electron graphene spectrum, all single wall carbon nanotubes (CNTs) that satisfy the condition n = 3p + m, where p is an integer, are metallic (see Refs. 3,18 for classification of CNTs). However, first principle and numerical tight-binding calculations show that only armchair CNTs (n = m) are truly metallic.…”

Section: Introductionmentioning

confidence: 99%

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Interband transitions in narrow-gap carbon nanotubes and graphene nanoribbons

Hartmann

Saroka

Portnoi

2019

Journal of Applied Physics

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Interband transitions in narrow-gap carbon nanotubes and graphene nanoribbons We use the robust nearest-neighbour tight-binding approximation to study on the same footing interband dipole transitions in narrow-bandgap carbon nanotubes and graphene nanoribbons. It is demonstrated that curvature effects in metallic singlewalled carbon nanotubes and edge effects in gapless graphene nanoribbons not only open up bang gaps, which typically correspond to THz frequencies, but also result in a giant enhancement of the probability of optical transitions across these gaps.Moreover, the matrix element of the velocity operator for these transitions has a universal value (equal to the Fermi velocity in graphene) when the photon energy coincides with the band-gap energy. Upon increasing the excitation energy, the transition matrix element first rapidly decreases (for photon energies remaining in the THz range but exceeding two band gap energies it is reduced by three orders of magnitude), and thereafter it starts to increase proportionally to the photon frequency.A similar effect occurs in an armchair carbon nanotube with a band gap opened and controlled by a magnetic field applied along the nanotube axis. There is a direct correspondence between armchair graphene nanoribbons and single-walled zigzag carbon nanotubes. The described sharp photon-energy dependence of the transition matrix element together with the van Hove singularity at the band gap edge of the considered quasi-one-dimensional systems make them promising candidates for active elements of coherent THz radiation emitters. The effect of Pauli blocking of low-energy interband transitions caused by residual doping can be suppressed by creating a population inversion using high-frequency (optical) excitation.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Interband transitions in narrow-gap carbon nanotubes and graphene nanoribbons

Hartmann

Saroka

Portnoi

2019

Journal of Applied Physics

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“…Hence, a complete characterization of the nano-oscillator requires knowledge of the vibrational modes as well as of the dynamic dielectric response function of the CNT. Work in this direction is in progress.Terahertz optics is an emerging field with promising applications including material characterization, tomographic imaging, as well as chemical and biological sensing [24,25]. Presently, development of THz technologies is hindered by difficulties in the generation and detection of THz electromagnetic fields.…”

mentioning

confidence: 99%

Ion-Nanotube Terahertz Oscillator

Schulten

2005

Phys. Rev. Lett.

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We report the intriguing dynamics of a potassium ion interacting with a 16 A carbon nanotube. The ion induces a strong dielectric response in the nanotube wall that can be described through a self-consistent tight-binding method. The polarization of the nanotube was found to play a critical role in the ion-nanotube interaction, which exhibits a low access barrier of only 1.05 kcal/mol and a deep, attractive well with a depth of about 30 kcal/mol. An ion bound in the nanotube is predicted to oscillate at a frequency of about 0.4 terahertz, dragging the electrons of the nanotube along. Besides its appealing nature in low-dimensional physics, such a nano-oscillator may serve as a room temperature terahertz wave detector.

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“…The search for effective terahertz (THz) radiation sources and detectors is one of the important trends of modern applied physics [1,2]. None of the existing THz emitters universally satisfies the application requirements.…”

mentioning

confidence: 99%

Stimulated emission of terahertz radiation by semiconductor microcavities

Kavokin,

Kaliteevski,

Abram

et al. 2010

Preprint

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We show that planar semiconductor microcavities in the strong coupling regime can be used as sources of stimulated terahertz (THz) radiation. Emitted THz photons would have a frequency of the spliting of the cavity polariton modes. The optical transition between upper and lower polariton branches is allowed due to mixing of the upper polariton state with one of excited exciton states. This transition is stimulated in the polariton laser regime.

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Electron/Electromagnetic Multiple Scattering and Localization

Cited by 3 publications

References 77 publications

Interband transitions in narrow-gap carbon nanotubes and graphene nanoribbons

Interband transitions in narrow-gap carbon nanotubes and graphene nanoribbons

Ion-Nanotube Terahertz Oscillator

Stimulated emission of terahertz radiation by semiconductor microcavities

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