Thermoelectrics in Coulomb-coupled quantum dots: Cotunneling and energy-dependent lead couplings

Nicklas Walldorf, Antti-Pekka Jauho, Kristen Kaasbjerg

Research output: Contribution to journalJournal articleResearchpeer-review

401 Downloads (Pure)


We study thermoelectric effects in Coulomb-coupled quantum-dot (CCQD) systems beyond lowest-order tunneling processes and the often applied wide-band approximation. To this end, we present a master-equation (ME) approach based on a perturbative T -matrix calculation of the charge and heat tunneling rates and transport currents. Applying the method to transport through a noninteracting single-level QD, we demonstrate excellent agreement with the Landauer-Büttiker theory when higher-order (cotunneling) processes are included in the ME. Next, we study the effect of cotunneling and energy-dependent lead couplings on the heat currents in a system of two CCQDs. We find that cotunneling processes (i) can dominate the off-resonant heat currents at low temperature and bias compared to the interdot interaction, and (ii) give rise to a pronounced reduction of the cooling power achievable with the recently demonstrated Maxwell’s demon coolingmechanism. Furthermore, we demonstrate that the cooling power can be boosted significantly by carefully engineering the energy dependence of the lead couplings to filter out undesired transport processes. Our findings emphasize the importance of higher-order cotunneling processes as well as engineered energy-dependent lead couplings in the optimization of the thermoelectric performance of CCQD systems.
Original languageEnglish
Article number115415
JournalPhysical Review B (Condensed Matter and Materials Physics)
Number of pages9
Publication statusPublished - 2017

Bibliographical note

©2017 American Physical Society


Dive into the research topics of 'Thermoelectrics in Coulomb-coupled quantum dots: Cotunneling and energy-dependent lead couplings'. Together they form a unique fingerprint.

Cite this