Enhancement of thermoelectric efficiency in triple quantum dots by the Dicke effect

Abstract

We theoretically study thermoelectric transport through a quantum dot coupled to two side quantum dots in the linear response regime by the nonequilibrium Green's function technique. Our results show that thermoelectric properties are strongly influenced by the Dicke effect. At low temperature, for small (very large) level shift and large interdot coupling the subradiant state contributes a sharp peak to the Dicke spectral line in the electrical and thermal conductance spectrum and leads to a strong violation of the Wiedemann-Franz law. As a result, the thermoelectric efficiency is strongly enhanced near the subradiant state. At relatively high temperature, the large tunneling coupling may be used to compensate the attenuation of the interference effect so that a considerable thermoelectric efficiency can still be obtained around the subradiant state. Moreover, the thermoelectric efficiency is also strongly dependent on the asymmetry parameter and intradot Coulomb interaction.