Dynamics of optically injected currents in carbon nanotubes

Charge transport in nanosized electronic systems is described by semiclassical or quantum kinetic equations that are often costly to solve numerically and difficult to reduce systematically to macroscopic balance equations for densities, currents, temperatures and other moments of macroscopic variables. The maximum entropy principle can be used to close the system of equations for the moments but its accuracy or range of validity are not always clear. In this paper, we compare numerical solutions of balance equations for nonlinear electron transport in semiconductor superlattices. The equations have been obtained from Boltzmann-Poisson kinetic equations very far from equilibrium for strong fields, either by the maximum entropy principle or by a systematic Chapman-Enskog perturbation procedure. Both approaches produce the same current-voltage characteristic curve for uniform fields. When the superlattices are DC voltage biased in a region where there are stable time periodic solutions corresponding to recycling and motion of electric field pulses, the differences between the numerical solutions produced by numerically solving both types of balance equations are smaller than the expansion parameter used in the perturbation procedure. These results and possible new research venues are discussed.

show abstract

“…Changing the collision operator so that it has relaxation time form [26] may allow a comparison similar to that in the present paper.…”

Section: Discussionmentioning

confidence: 95%

Maximum Entropy Closure of Balance Equations for Miniband Semiconductor Superlattices

Bonilla

Carretero

2016

Entropy

View full text Add to dashboard Cite

show abstract

“…denoting the difference between valence and conduction Fermi-Dirac functions. Equation (32) shows that the initial excess population ∆f undergoes an exponential-decay dynamics according to the µ-dependent decay rate in (33), whose relative change with respect to the µ = 0 case is given by…”

Section: Effects Of the Chemical Potentialmentioning

confidence: 99%

“…These approaches, however, fail in capturing the intrinsically dissipative nature of the phonon bath. On the other hand, treating electronphonon coupling in SWNTs via the Boltzmann-equation schemes 33,34 does not allow one to account for electronic phase coherence.…”

Section: Introductionmentioning

confidence: 99%

Electron-phonon coupling in metallic carbon nanotubes: Dispersionless electron propagation despite dissipation

2015

View full text Add to dashboard Cite

A recent study [Rosati, Dolcini, and Rossi, Appl. Phys. Lett. 106, 243101 (2015)] has predicted that, while in semiconducting single-walled carbon nanotubes (SWNTs) an electronic wave packet experiences the typical spatial diffusion of conventional materials, in metallic SWNTs its shape remains essentially unaltered up to micrometer distances at room temperature, even in the presence of the electron-phonon coupling. Here, by utilizing a Lindblad-based density-matrix approach enabling us to account for both dissipation and decoherence effects, we test such a prediction by analyzing various aspects that were so far unexplored. In particular, accounting for initial nonequilibrium excitations, characterized by an excess energy E0, and including both intra-and interband phonon scattering, we show that for realistically high values of E0 the electronic diffusion is extremely small and nearly independent of its energetic distribution, in spite of a significant energy-dissipation and decoherence dynamics. Furthermore, we demonstrate that the effect is robust with respect to the variation of the chemical potential. Our results thus suggest that metallic SWNTs are a promising platform to realise quantum channels for the non-dispersive transmission of electronic wave packets.

show abstract

Dynamics of optically injected currents in carbon nanotubes

Cited by 2 publications

References 18 publications

Maximum Entropy Closure of Balance Equations for Miniband Semiconductor Superlattices

Maximum Entropy Closure of Balance Equations for Miniband Semiconductor Superlattices

Electron-phonon coupling in metallic carbon nanotubes: Dispersionless electron propagation despite dissipation

Contact Info

Product

Resources

About