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Philippe Lambin - One of the best experts on this subject based on the ideXlab platform.
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radius and chirality dependence of the radial breathing mode and the g band phonon modes of single walled carbon nanotubes
Physical Review B, 2006Co-Authors: V N Popov, Philippe LambinAbstract:The radial breathing and G-band vibrational modes of all 300 single-walled carbon nanotubes in the radius range from 2 to 12 A were calculated within a symmetry-adapted nonorthogonal tight-binding model. The dynamical matrix was calculated within this model using the linear-response approximation. The obtained phonon frequencies show well-expressed radius and chirality dependence and Family Behavior. The curvatureinduced effects on the frequencies are found to be important for smalland moderate-radius tubes. The strong electron-phonon interactions in metallic tubes bring about Kohn anomalies of certain phonon branches. Among the Raman-active phonons, these interactions have strongest effect on the longitudinal tangential A1 phonons of metallic tubes, whose frequency becomes lower than that of the transverse tangential A1 phonons. The calculated frequencies are compared to available theoretical and experimental data.
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electron phonon and electron photon interactions and resonant raman scattering from the radial breathing mode of single walled carbon nanotubes
Physical Review B, 2005Co-Authors: V N Popov, Luc Henrard, Philippe LambinAbstract:The resonance Raman profile of the radial-breathing mode is calculated for all 300 single-walled carbon nanotubes in the radius range from 2 A to 12 A and for all optical transitions up to 3.5 eV using a symmetryadapted nonorthogonal tight-binding model V. N. Popov, New J. Phys. 6 ,1 72004. The influence of the electron-phonon and electron-photon interactions on the Raman intensity is studied using an approximate expression for the intensity in the vicinity of each optical transition as the product of the electron-phonon coupling matrix element, the momentum matrix element, and the effective mass raised to different powers. The dependence of the latter three quantities and the maximum Raman intensity on the nanotube radius, the chiral angle, and the optical transition energy is discussed in detail. In particular, the points of the corresponding plots exhibit Family Behavior of three different types. It is shown that the widespread practice to neglect the electron-photon and electron-phonon interactions in the estimation of the intensity can lead to incorrect prediction of the Raman spectra.
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electron phonon and electron photon interactions and resonant raman scattering from the radial breathing mode of single walled carbon nanotubes
Physical Review B, 2005Co-Authors: V N Popov, Luc Henrard, Philippe LambinAbstract:The resonance Raman profile of the radial-breathing mode is calculated for all 300 single-walled carbon nanotubes in the radius range from $2\phantom{\rule{0.3em}{0ex}}\mathrm{\AA{}}\phantom{\rule{0.3em}{0ex}}\text{to}\phantom{\rule{0.3em}{0ex}}12\phantom{\rule{0.3em}{0ex}}\mathrm{\AA{}}$ and for all optical transitions up to $3.5\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ using a symmetry-adapted nonorthogonal tight-binding model [V. N. Popov, New J. Phys. 6, 17 (2004)]. The influence of the electron-phonon and electron-photon interactions on the Raman intensity is studied using an approximate expression for the intensity in the vicinity of each optical transition as the product of the electron-phonon coupling matrix element, the momentum matrix element, and the effective mass raised to different powers. The dependence of the latter three quantities and the maximum Raman intensity on the nanotube radius, the chiral angle, and the optical transition energy is discussed in detail. In particular, the points of the corresponding plots exhibit Family Behavior of three different types. It is shown that the widespread practice to neglect the electron-photon and electron-phonon interactions in the estimation of the intensity can lead to incorrect prediction of the Raman spectra.
V N Popov - One of the best experts on this subject based on the ideXlab platform.
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radius and chirality dependence of the radial breathing mode and the g band phonon modes of single walled carbon nanotubes
Physical Review B, 2006Co-Authors: V N Popov, Philippe LambinAbstract:The radial breathing and G-band vibrational modes of all 300 single-walled carbon nanotubes in the radius range from 2 to 12 A were calculated within a symmetry-adapted nonorthogonal tight-binding model. The dynamical matrix was calculated within this model using the linear-response approximation. The obtained phonon frequencies show well-expressed radius and chirality dependence and Family Behavior. The curvatureinduced effects on the frequencies are found to be important for smalland moderate-radius tubes. The strong electron-phonon interactions in metallic tubes bring about Kohn anomalies of certain phonon branches. Among the Raman-active phonons, these interactions have strongest effect on the longitudinal tangential A1 phonons of metallic tubes, whose frequency becomes lower than that of the transverse tangential A1 phonons. The calculated frequencies are compared to available theoretical and experimental data.
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electron phonon and electron photon interactions and resonant raman scattering from the radial breathing mode of single walled carbon nanotubes
Physical Review B, 2005Co-Authors: V N Popov, Luc Henrard, Philippe LambinAbstract:The resonance Raman profile of the radial-breathing mode is calculated for all 300 single-walled carbon nanotubes in the radius range from 2 A to 12 A and for all optical transitions up to 3.5 eV using a symmetryadapted nonorthogonal tight-binding model V. N. Popov, New J. Phys. 6 ,1 72004. The influence of the electron-phonon and electron-photon interactions on the Raman intensity is studied using an approximate expression for the intensity in the vicinity of each optical transition as the product of the electron-phonon coupling matrix element, the momentum matrix element, and the effective mass raised to different powers. The dependence of the latter three quantities and the maximum Raman intensity on the nanotube radius, the chiral angle, and the optical transition energy is discussed in detail. In particular, the points of the corresponding plots exhibit Family Behavior of three different types. It is shown that the widespread practice to neglect the electron-photon and electron-phonon interactions in the estimation of the intensity can lead to incorrect prediction of the Raman spectra.
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electron phonon and electron photon interactions and resonant raman scattering from the radial breathing mode of single walled carbon nanotubes
Physical Review B, 2005Co-Authors: V N Popov, Luc Henrard, Philippe LambinAbstract:The resonance Raman profile of the radial-breathing mode is calculated for all 300 single-walled carbon nanotubes in the radius range from $2\phantom{\rule{0.3em}{0ex}}\mathrm{\AA{}}\phantom{\rule{0.3em}{0ex}}\text{to}\phantom{\rule{0.3em}{0ex}}12\phantom{\rule{0.3em}{0ex}}\mathrm{\AA{}}$ and for all optical transitions up to $3.5\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ using a symmetry-adapted nonorthogonal tight-binding model [V. N. Popov, New J. Phys. 6, 17 (2004)]. The influence of the electron-phonon and electron-photon interactions on the Raman intensity is studied using an approximate expression for the intensity in the vicinity of each optical transition as the product of the electron-phonon coupling matrix element, the momentum matrix element, and the effective mass raised to different powers. The dependence of the latter three quantities and the maximum Raman intensity on the nanotube radius, the chiral angle, and the optical transition energy is discussed in detail. In particular, the points of the corresponding plots exhibit Family Behavior of three different types. It is shown that the widespread practice to neglect the electron-photon and electron-phonon interactions in the estimation of the intensity can lead to incorrect prediction of the Raman spectra.
Mildred S Dresselhaus - One of the best experts on this subject based on the ideXlab platform.
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chirality dependence of exciton effects in single wall carbon nanotubes tight binding model
Physical Review B, 2007Co-Authors: J Jiang, Ge G Samsonidze, Riichiro Saito, A Jorio, S G Chou, G Dresselhaus, Mildred S DresselhausAbstract:We have studied the exciton properties of single-wall carbon nanotubes by solving the Bethe-Salpeter equation within tight-binding models. The screening effect of the $\ensuremath{\pi}$ electrons in carbon nanotubes is treated within the random phase and static screened approximations. The exciton wave functions along the tube axis and circumference are discussed as a function of $(n,m)$. A $2n+m=\mathrm{const}$ Family Behavior is found in the exciton wave function length, excitation energy, binding energy, and environmental shift. This Family Behavior is understood in terms of the trigonal warping effect around the $K$ point of a graphene layer and curvature effects. The large Family spread in the excitation energy of the Kataura plot is found to come from the single-particle energy.
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Family Behavior of the optical transition energies in single wall carbon nanotubes of smaller diameters
Applied Physics Letters, 2004Co-Authors: Ge G Samsonidze, Riichiro Saito, Nagao Kobayashi, A Gruneis, J Jiang, A Jorio, S G Chou, G Dresselhaus, Mildred S DresselhausAbstract:Using the extended tight-binding model that allows bond lengths and angles to vary, the optical transition energies Eii in single-wall carbon nanotubes are calculated as a function of inverse tube diameter. After geometrical structure optimization, the 2n+m=constant Family Behavior observed in photoluminescence (PL) experiments is obtained, and detailed agreement between the calculations and PL experiments is achieved after including many-body corrections.
Luc Henrard - One of the best experts on this subject based on the ideXlab platform.
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electron phonon and electron photon interactions and resonant raman scattering from the radial breathing mode of single walled carbon nanotubes
Physical Review B, 2005Co-Authors: V N Popov, Luc Henrard, Philippe LambinAbstract:The resonance Raman profile of the radial-breathing mode is calculated for all 300 single-walled carbon nanotubes in the radius range from 2 A to 12 A and for all optical transitions up to 3.5 eV using a symmetryadapted nonorthogonal tight-binding model V. N. Popov, New J. Phys. 6 ,1 72004. The influence of the electron-phonon and electron-photon interactions on the Raman intensity is studied using an approximate expression for the intensity in the vicinity of each optical transition as the product of the electron-phonon coupling matrix element, the momentum matrix element, and the effective mass raised to different powers. The dependence of the latter three quantities and the maximum Raman intensity on the nanotube radius, the chiral angle, and the optical transition energy is discussed in detail. In particular, the points of the corresponding plots exhibit Family Behavior of three different types. It is shown that the widespread practice to neglect the electron-photon and electron-phonon interactions in the estimation of the intensity can lead to incorrect prediction of the Raman spectra.
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electron phonon and electron photon interactions and resonant raman scattering from the radial breathing mode of single walled carbon nanotubes
Physical Review B, 2005Co-Authors: V N Popov, Luc Henrard, Philippe LambinAbstract:The resonance Raman profile of the radial-breathing mode is calculated for all 300 single-walled carbon nanotubes in the radius range from $2\phantom{\rule{0.3em}{0ex}}\mathrm{\AA{}}\phantom{\rule{0.3em}{0ex}}\text{to}\phantom{\rule{0.3em}{0ex}}12\phantom{\rule{0.3em}{0ex}}\mathrm{\AA{}}$ and for all optical transitions up to $3.5\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ using a symmetry-adapted nonorthogonal tight-binding model [V. N. Popov, New J. Phys. 6, 17 (2004)]. The influence of the electron-phonon and electron-photon interactions on the Raman intensity is studied using an approximate expression for the intensity in the vicinity of each optical transition as the product of the electron-phonon coupling matrix element, the momentum matrix element, and the effective mass raised to different powers. The dependence of the latter three quantities and the maximum Raman intensity on the nanotube radius, the chiral angle, and the optical transition energy is discussed in detail. In particular, the points of the corresponding plots exhibit Family Behavior of three different types. It is shown that the widespread practice to neglect the electron-photon and electron-phonon interactions in the estimation of the intensity can lead to incorrect prediction of the Raman spectra.
Ge G Samsonidze - One of the best experts on this subject based on the ideXlab platform.
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chirality dependence of exciton effects in single wall carbon nanotubes tight binding model
Physical Review B, 2007Co-Authors: J Jiang, Ge G Samsonidze, Riichiro Saito, A Jorio, S G Chou, G Dresselhaus, Mildred S DresselhausAbstract:We have studied the exciton properties of single-wall carbon nanotubes by solving the Bethe-Salpeter equation within tight-binding models. The screening effect of the $\ensuremath{\pi}$ electrons in carbon nanotubes is treated within the random phase and static screened approximations. The exciton wave functions along the tube axis and circumference are discussed as a function of $(n,m)$. A $2n+m=\mathrm{const}$ Family Behavior is found in the exciton wave function length, excitation energy, binding energy, and environmental shift. This Family Behavior is understood in terms of the trigonal warping effect around the $K$ point of a graphene layer and curvature effects. The large Family spread in the excitation energy of the Kataura plot is found to come from the single-particle energy.
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Family Behavior of the optical transition energies in single wall carbon nanotubes of smaller diameters
Applied Physics Letters, 2004Co-Authors: Ge G Samsonidze, Riichiro Saito, Nagao Kobayashi, A Gruneis, J Jiang, A Jorio, S G Chou, G Dresselhaus, Mildred S DresselhausAbstract:Using the extended tight-binding model that allows bond lengths and angles to vary, the optical transition energies Eii in single-wall carbon nanotubes are calculated as a function of inverse tube diameter. After geometrical structure optimization, the 2n+m=constant Family Behavior observed in photoluminescence (PL) experiments is obtained, and detailed agreement between the calculations and PL experiments is achieved after including many-body corrections.
