Browsing by Subject "Coulomb drag effect"

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    Coulomb drag effect in parallel cylindrical quantum wires
    (Pergamon Press, 1996) Tanatar, Bilal
    We study the Coulomb drag rate for electrons in two parallel quantum wires. The double-quantum wire structure is modeled for a GaAs material with cylindrical wires having infinite potential barriers. The momentum transfer rate between the wires (Coulomb drag effect) is calculated as a function of temperature for several wire separation distances. We employ the full wave vector and frequency dependent random-phase approximation (RPA) at finite temperature to describe the effective interwire Coulomb interaction. We find that the drag rate at high temperatures (i.e., T ≥ EF/2) is dominated by the collective modes (plasmons) of the system similar to the case in double-well structures. Including the local-field effects in an approximate way we estimate the importance of intrawire correlations to be significant. Copyright © 1996 Published by Elsevier Science Ltd.
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    Coulomb drag effect in parallel quantum dots
    (American Institute of Physics, 2009) Tanatar, Bilal; Moldoveanu, V.
    We study theoretically the electronic transport in parallel few-level quantum dots in the presence of both intradot and interdot long-range Coulomb interaction. Each dot is connected to two leads and the steady-state currents are calculated within the Keldysh formalism using the random-phase approximation for the interacting Green functions. Due to the momentum transfer mechanism between the two systems it is possible to get a nonvanishing current through an unbiased Coulomb-blockaded dot if the other dot is set in the nonlinear transport regime. The transitions between the levels of the passive dot reduce the drag current and lead to negative differential conductance.
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    Dynamical correlations in Coulomb drag effect
    (Elsevier, 2003) Tanatar, Bilal; Davoudi, B.; Hu, B.Y.-K.
    Motivated by recent Coulomb drag experiments in pairs of low-density two-dimensional (2D) electron gases, we investigate the influence of correlation effects on the interlayer drag rate as a function of temperature. We use the self-consistent field method to calculate the intra and interlayer local-field factors Gij(q,T) which embody the short-range correlation effects. We calculate the transresistivity using the screened effective interlayer interactions that result from incorporating these local-field factors within various approximation schemes. Our results suggest that dynamic (frequency dependent) correlations play an important role in enhancing the Coulomb drag rate.