Wednesday, September 5, 2012

1209.0506 (David M. -T. Kuo et al.)

Thermoelectric properties of a chain of coupled quantum dots embedded in
a nanowire
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David M. -T. Kuo, Yia-Chung Chang
The thermoelectric properties of a chain of coupled quantum dots (CCQD) embedded in a nanowire are theoretically investigated in the Coulomb blockade regime. An extended Hubbard model is employed to simulate the CCQD nanowire system. The charge and heat currents are calculated in the framework of Keldysh Green's function technique. We obtained a closed-form Landauer expression for the transmission coefficient of the CCQD system. The electrical conductance {\color{blue}($G_e$)}, Seebeck coefficient (S), thermal conductance, and figure of merit (ZT) are numerically calculated and analyzed in the linear response regime. When thermal conductance is dominated by phonon carriers, the optimization of ZT is determined by the power factor ($pF=S^2G_e$). We find that off-resonant tunneling processes, asymmetrical interdot electron Coulomb interactions, weak interdot hopping strengths and asymmetrical tunneling rates between QDs and electrodes are not favored in the optimization of ZT as a result they suppress the power factor of junction system.
View original: http://arxiv.org/abs/1209.0506

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