The Experts below are selected from a list of 1611 Experts worldwide ranked by ideXlab platform

Yoshiyuki Kawazoe - One of the best experts on this subject based on the ideXlab platform.

  • stable geometries and magnetic properties of single walled Carbon Nanotubes doped with 3d transition metals a first principles study
    Physical Review B, 2004
    Co-Authors: Yosuke Yagi, Tina Marie Briere, Marcel H F Sluiter, Vijay Kumar, Amir A Farajian, Yoshiyuki Kawazoe
    Abstract:

    The interaction of 3d transition metal atoms and dimers with a single-walled Armchair Carbon Nanotube has been investigated by first-principles density functional calculations. For Fe-, Co-, and Ni-doped (4,4) Nanotubes, outside adsorption sites are the most favorable. The interactions are largely ferromagnetic for Fe and Co, with the local magnetic moments of the dimers being similar to the free dimers. However, for Ni most structures are nonmagnetic. We have also examined the effects of curvature with calculations for graphene and the (8,8) Nanotube. For the (8,8) Nanotube, the interaction of Co becomes more favorable inside the Nanotube. Doping of a single Co atom transforms the (4,4) and (8,8) Nanotubes into half-metals. These results are useful for spintronics applications and could help in the development of magnetic nanostructures and metallic Nanotube coatings.

L I Glazman - One of the best experts on this subject based on the ideXlab platform.

  • quantum criticality in a mott pn junction in an Armchair Carbon Nanotube
    Physical Review Letters, 2011
    Co-Authors: Wei Chen, A V Andreev, L I Glazman
    Abstract:

    In an Armchair Carbon Nanotube pn junction the p and n regions are separated by a region of a Mott insulator, which can backscatter electrons only in pairs. We predict a quantum-critical behavior in such a pn junction. Depending on the junction's built-in electric field E, its conductance G scales either to zero or to 4e(2)/h as the temperature T is lowered. The two types of the G(T) dependence indicate the existence, at some special value of E, of an intermediate quantum-critical point with a finite conductance G<4e(2)/h. This makes the pn junction drastically different from a simple potential barrier in a Luttinger liquid.

Wanli Guo - One of the best experts on this subject based on the ideXlab platform.

  • validation of the non local elastic shell model for studying longitudinal waves in single walled Carbon Nanotubes
    Nanotechnology, 2006
    Co-Authors: Lifeng Wang, Wanli Guo
    Abstract:

    This study deals with the dispersion of longitudinal waves in a single-walled Armchair Carbon Nanotube, focusing on the effect of the microstructure of the Carbon Nanotube on the wave dispersion. To reveal the effect analytically, the Carbon Nanotube is modelled as a non-local elastic cylindrical shell in the study. The dynamic equation of the non-local elastic cylindrical shell is established and the corresponding dispersion relation of longitudinal waves is derived. These analytic results are verified via molecular dynamics simulations, based on the Terroff–Brenner potential, for the propagation of various longitudinal waves in three single-walled Armchair Carbon Nanotubes. The molecular dynamics simulations indicate that the longitudinal wave dispersion predicted by the model of the non-local elastic cylindrical shell shows a good agreement with that of molecular dynamics simulations in a wide frequency range up to the terahertz region. They also show that both the microstructure of the Carbon Nanotube and the coupling between the longitudinal wave and the radial motion play an important role in the dispersion of longitudinal waves in a single-walled Armchair Carbon Nanotube.

Yosuke Yagi - One of the best experts on this subject based on the ideXlab platform.

  • stable geometries and magnetic properties of single walled Carbon Nanotubes doped with 3d transition metals a first principles study
    Physical Review B, 2004
    Co-Authors: Yosuke Yagi, Tina Marie Briere, Marcel H F Sluiter, Vijay Kumar, Amir A Farajian, Yoshiyuki Kawazoe
    Abstract:

    The interaction of 3d transition metal atoms and dimers with a single-walled Armchair Carbon Nanotube has been investigated by first-principles density functional calculations. For Fe-, Co-, and Ni-doped (4,4) Nanotubes, outside adsorption sites are the most favorable. The interactions are largely ferromagnetic for Fe and Co, with the local magnetic moments of the dimers being similar to the free dimers. However, for Ni most structures are nonmagnetic. We have also examined the effects of curvature with calculations for graphene and the (8,8) Nanotube. For the (8,8) Nanotube, the interaction of Co becomes more favorable inside the Nanotube. Doping of a single Co atom transforms the (4,4) and (8,8) Nanotubes into half-metals. These results are useful for spintronics applications and could help in the development of magnetic nanostructures and metallic Nanotube coatings.

Wei Chen - One of the best experts on this subject based on the ideXlab platform.

  • quantum criticality in a mott pn junction in an Armchair Carbon Nanotube
    Physical Review Letters, 2011
    Co-Authors: Wei Chen, A V Andreev, L I Glazman
    Abstract:

    In an Armchair Carbon Nanotube pn junction the p and n regions are separated by a region of a Mott insulator, which can backscatter electrons only in pairs. We predict a quantum-critical behavior in such a pn junction. Depending on the junction's built-in electric field E, its conductance G scales either to zero or to 4e(2)/h as the temperature T is lowered. The two types of the G(T) dependence indicate the existence, at some special value of E, of an intermediate quantum-critical point with a finite conductance G<4e(2)/h. This makes the pn junction drastically different from a simple potential barrier in a Luttinger liquid.