1,300 research outputs found
Thermoelectric Amplification of Phonons in Graphene
Amplification of acoustic phonons due to an external temperature gredient
() in Graphene was studied theoretically. The threshold temperature
gradient at which absorption switches over to amplification
in Graphene was evaluated at various frequencies and temperatures
. For and frequency , . The calculation was done in the regime at . The
dependence of the normalized () on the frequency
and the temperature gradient are evaluated numerically and
presented graphically. The calculated for Graphene is lower
than that obtained for homogeneous semiconductors () , Superlattices , Cylindrical Quantum Wire . This makes Graphene a much better material for thermoelectric
phonon amplifier.Comment: 12 Pages, 6 figure
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
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