2,940 research outputs found
External electric field effect on electron transport in carbon nanotubes
Electronic transport properties of carbon nanotubes are studied theoretically
in the presence of external electric field E(t) by using the Boltzmann's
transport with constant relaxation time. An analytical expression for the
current densities of the nanotubes are obtained. It is observed that the
current density-electric field characteristics of the CNs exhibit total
self-induced transparency and absolute negative conductivityComment: 5 pages, 2 figure
Appearance of Negative Differential Conductivity in Graphene Nanoribbons at High-Harmonics
We theoretically study current dynamics of graphene nanoribbons subject to
bias dc and ac driven fields. We showed that graphene nanoribbons exhibit
negative high-harmonic differential conductivity. Negative differential
conductivity appears when bias electric filed is in the neighborhood of applied
ac filed amplitude. We also observe both even and odd high-harmonic negative
differential conductivity at wave mixing of two commensurate frequencies. The
even harmonics are more pronounced than the odd harmonics. A possible use of
the present method for generating terahertz frequencies at even harmonics in
graphene is suggested.Comment: 6 pages, 3 figure
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