Analytic treatment of the thermoelectric properties for two coupled quantum dots threaded by magnetic fields

TL;DR

This paper provides an analytical framework for understanding and optimizing the thermoelectric properties of coupled quantum dots under magnetic fields, revealing significant enhancements in thermopower and efficiency.

Contribution

It introduces fully analytic expressions for thermoelectric properties of coupled quantum dots with magnetic flux, aiding device design and understanding interference effects.

Findings

Thermopower S can be increased by over ten times with magnetic flux.

Figure of merit ZT can be enhanced by more than a hundred times.

Magnetic flux improves device performance at maximum power output.

Abstract

Coupled double quantum dots (c-2QD) connected to leads have been widely adopted as prototype model systems to verify interference effects on quantum transport at the nanoscale. We provide here an analytic study of the thermoelectric properties of c-2QD systems pierced by a uniform magnetic field. Fully analytic and easy-to-use expressions are derived for all the kinetic functionals of interest. Within the Green 0 s function formalism, our results allow a simple inexpensive procedure for the theoretical description of the thermoelectric phenomena for different chemical potentials and temperatures of the reservoirs, different threading magnetic fluxes, dot energies and interdot interactions; moreover they provide an intuitive guide to parametrize the system Hamiltonian for the design of best performing realistic devices. We have found that the thermopower S can be enhanced by more than ten times and the figure of merit ZT by more than hundred times by the presence of a threading magnetic field. Most important, we show that the magnetic flux increases also the performance of the device under maximum power output conditions.