Colossal enhancement in thermoelectric efficiency of weakly coupled double quantum dot system

A colossal enhancement in thermoelectric efficiency, ZT, of coupled double quantum dot (DQD) system in series configuration, have been predicted in the Coulomb blockade regime for a non-magnetic case, as a result of very weak interdot tunnel coupling and highly asymmetric dot-lead couplings using Keldysh nonequilibrium Green function approach. Such an enhancement (which leads to saturation in the extreme case) of ZT as a result of tuning of coupling parameters is understood in terms of bipolar effect. These findings suggest that highly asymmetric DQD system, with very weak interdot tunnel coupling can be used to design more efficient thermoelectric devices. (C) 2011 American Institute of Physics. [doi:10.1063/1.3662946]