Quantum electron transport through carbon nanotubes with electron-phonon coupling
Computing time of the conductance of metallic (5,5)-carbon nanotubes with various lengths. The black circles represent the computing time when we use the Chebyshev polynomial development for simulation. For comparison, the computing time of simulation using the split-operator method is shown by white circles. In the inset, we show the computing time for the short nanotube.
Calculated time-dependent diffusion coefficients of the (5,5)-carbon nanotubes. White circles indicate the diffusion coefficient of the nanotube without any scattering effects. Black circles, triangles, and squares represent the the diffusion coefficients in the case of the different potential magnitudes and concentrations .
(a) Calculated diffusion coefficient of the metallic (5,5)-carbon nanotube at the Fermi energy. The straight broken line represents the time-dependent behavior of the diffusion coefficient for no scattering effects. The electron-phonon scattering saturates the diffusion coefficient, as shown by the bold curve. (b) Calculated resistance vs channel-length characteristic of the (5,5)-carbon nanotube. In the case of no electron-phonon scattering, the ballistic transport is realized. Therefore, resistance takes a constant value independent of nanotube length, as shown by the broken line. Resistance is proportional to length, when the nanotube is much longer than the mean free path.
Calculated resistivities of the (5,5)-carbon nanotubes as a function of temperature. We define resistivity as the resistance per unit length in this work. Resistivity is proportional to the temperature.
Calculated relaxation times and mean free paths of the (5,5)-carbon nanotubes using the Fermi golden rule for different impurity potential magnitudes and concentrations .
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