Thermoelectric properties of interacting double quantum dots

Abstract

We investigate the thermoelectric transport properties of an interacting parallel double quantum dot in the Coulomb-blockade regime. Building on an analytical solution based on an equation-of-motion technique, we extend the formalism for the asymmetrically coupled situation and provide compact closed-form expressions for steady-state currents together with the differential conductance, Seebeck coefficient, and thermal conductance. We determine the operating points that maximize efficiency and output power of the system, clarifying their relation to standard near-equilibrium ZT expressions. We further study the thermal rectification in both the open- and closed-circuit configurations and derive an expression for the open-circuit case. Interaction-induced resonances are understood in terms of the poles of the resulting Green's function, generating gate and bias dependent regions of enhanced efficiency at finite power, negative differential thermal conductance, and finite thermal rectification.