Thermoelectric performance of quantum dots embedded in an Aharonov-Bohm ring: a Pauli master equation approach

Abstract

Within linear response theory using Pauli master equation approach, we have investigated the thermoelectric properties of quantum dots (QDs) embedded in an Aharonov-Bohm (AB) ring weakly coupled to two metallic electrodes. This study explores the impact of magnetic flux on thermoelectric transport, emphasizing the role of quantum interference induced by the flux. When the magnetic flux is varied from 0 to one quantum of flux $\Phi = \Phi_{0} = \frac{h}{e}$, both the electrical conductance and the thermoelectric figure of merit ($ZT$) significantly increase by two order of magnitude. Moreover, our investigation into the effects of onsite and inter-site Coulomb interactions in this nanojunction indicates that an optimal $ZT$ is attained with moderate onsite Coulomb interaction and minimal inter-site Coulomb interaction. We briefly discussed the effects of asymmetric arrangements of triple QDs within an AB ring. However, within our parameter regime, a symmetric arrangement offers superior thermoelectric performance compared to asymmetric configurations. Furthermore, we explored how increasing the number of QDs in the ring enhances the thermoelectric properties, resulting in a potential $ZT$ value of around $0.43$. This study shows that arranging multiple QDs symmetrically in an AB ring can result in significant thermoelectric performance in nanostructured system at low temperatures.