Plasma excitations for cylindrical nanotubes with spin splitting

Gumbs, Godfrey; Abranyos, Yonatan; McNeish, Tibab

doi:10.1088/0953-8984/19/10/106213

Cited by 3 publications

(7 citation statements)

References 38 publications

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“…The two kinds of free carriers are further deexcited by inelastic electron-electron (e-e) scatterings. The [30][31][32] but also to other CN-related systems, such as a pair of parallel CN's 33 as well as a array of singlewalled 34 35 and multishell 36 CN's. The transferred momentum (q) and angular momentum (L) remain conserved in the e-e interactions, 30 and cause the rich and interesting excitation spectra for each CN.…”

Section: Introductionmentioning

confidence: 99%

Inelastic Coulomb Scatterings of Doped Armchair Carbon Nanotubes

Chiu¹,

Lee²,

Lin³

2010

J. Nanosci. Nanotech.

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For doped armchair carbon nanotubes, the free electrons in the conduction bands would cause the intraband single-particle and collective excitations. Both kinds of excitations would be split into two modes because of two different Fermi-momentum states (kF'S). The excited carriers might be deexcited through such Coulomb excitations. Regarding the case where the transferred momentum L = 0, the two single-particle and the lower-frequency collective excitation modes could be the efficient deexcitation channels. In the lowest bands, the decay rates of the electron states exhibit weak Fermi energy (E(F)) dependence, but the decay rates of the hole states become greater with the increase of E(F) except for the right-side k(F). Concerning the states in the higher bands, the L not equal 0 excitations also take part in the deexcitation processes. Both the electron and hole states have the same decay rates except for the case where the carriers decay to the lowest states. The decay rates contrast sharply with those of undoped carbon nanotubes and two-dimensional intercalated graphenes. It is domenated by the Fermi energy, the geometric structure and the dimensionalities. The femtosecond time-resolved photoelectron, transmission and fluorescence spectroscopies could be used to verify the predicted results.

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Section: Introductionmentioning

confidence: 99%

Inelastic Coulomb Scatterings of Doped Armchair Carbon Nanotubes

Chiu¹,

Lee²,

Lin³

2010

J. Nanosci. Nanotech.

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“…The electron eigenstates are labeled by quantum numbers representing its two degrees of freedom. 10,11 These are the wave number k z along the axis of the nanotube and the angular momentum quantum number l around its axis. The SOI shifts and splits the energy levels giving eigenstates which may be interpreted as a superposition of the | ↑ and | ↓ spin states.…”

Section: Introductionmentioning

confidence: 99%

“…For nanotubes, the Rashba field has a small effect since it is averaged over the circumference [3][4][5][6]. However, when electrostatic gates are applied to carbon nanotubes, and in the vicinity of a van Hove singularity [10], the Rashba SOI is enhanced and could lead to observable effects.…”

Section: Introductionmentioning

confidence: 99%

“…We will assume that the nanotube we are dealing with is of high quality but will investigate the role played by disorder within the potential barrier on the electron transport. The electron eigenstates are labeled by quantum numbers representing its two degrees of freedom [10,11]. These are the wavenumber k z along the axis of the nanotube and the angular momentum quantum number l around its axis.…”

Section: Introductionmentioning

confidence: 99%

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Spin-dependent scattering by a potential barrier on a nanotube

Abranyos¹,

Gumbs²,

Fekete³

2010

J. Phys.: Condens. Matter

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The electron spin effects on the surface of a nanotube have been considered through the spin-orbit interaction (SOI), arising from the electron confinement on the surface of the nanotube. This is of the same nature as the Rashba-Bychkov SOI at a semiconductor heterojunction. We estimate the effect of disorder within a potential barrier on the transmission probability. Using a continuum model, we obtain analytic expressions for the spin-split energy bands for electrons on the surface of nanotubes in the presence of SOI. First we calculate analytically the amplitudes of scattering from a potential barrier located around the axis of the nanotube into spin-dependent states. The effect of disorder on the scattering process is included phenomenologically and induces a reduction in the transition probability. We analyze the relative role of SOI and disorder in the transmission probability which depends on the angular and linear momentum of the incoming particle, and its spin orientation. Finally we demonstrate that in the presence of disorder, perfect transmission may not be achieved for finite barrier heights.

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“…[1][2][3][4][5][6] Their extraordinary strength, unique electrical properties and their ability to conduct heat efficiently have generated considerable interest among both experimentalists and theoreticians. [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] Nanotubes may also be produced by synthesis methods, for instance multi-wall nanotubes (MWNTs) which consist of multiple layers of graphene rolled in on themselves to form a cylindrical tube. There are two models which can be used to describe the structures of multi-wall nanotubes.…”

Section: Introductionmentioning

confidence: 99%

Model of plasmon excitations in a bundle and a two-dimensional array of nanotubes

2008

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We calculate the plasma excitations in a bundle as well as a two-dimensional (2D) periodic array of aligned parallel multishell nanotubes on a substrate. The carbon nanotubes are oriented perpendicular to the substrate. The model we use for the system is an electron gas confined to the surface of an infinitely long cylinder embedded in a background dielectric medium. Electron tunneling between individual tubules is neglected. We include the Coulomb interaction between electrons on the same tubule and on different tubules for the same nanotube and neighboring nanotubes. We present a self-consistent field theory for the dispersion equation for intrasubband and intersubband plasmon excitations. For both the bundle and 2D array of aligned parallel nanotubes, the dispersion relation of the collective modes is determined by a three-dimensional wave vector with components in the direction of the nanotube axes and in the transverse directions. The dispersion equation is solved numerically for a singlewall nanotube 2D array as well as a bundle, and the plasmon excitation energies are obtained as a function of wave vector. The intertube Coulomb interaction couples plasmons with different angular momenta m in individual nanotubes, lifting the ±m degeneracy of the single-nanotube modes. This effect is analyzed numerically as a function of the separation between the tubules. We show that the translational symmetry of the lattice is maintained in the plasmon spectrum for the periodic array, and the plasmon energies have a periodic dependence on the transverse wave vector q ⊥ . For the bundle, the Coulomb interaction between nanotubes gives rise to optical plasmon excitations.

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Plasma excitations for cylindrical nanotubes with spin splitting

Cited by 3 publications

References 38 publications

Inelastic Coulomb Scatterings of Doped Armchair Carbon Nanotubes

Inelastic Coulomb Scatterings of Doped Armchair Carbon Nanotubes

Spin-dependent scattering by a potential barrier on a nanotube

Model of plasmon excitations in a bundle and a two-dimensional array of nanotubes

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