Roles of vacuum tunnelling and contact mechanics in single-molecule thermopower

Thermoelectric properties of Marcus molecular junctions

In the present work we theoretically analyze thermoelectric transport in single-molecule junctions (SMJ) characterized by strong interactions between electrons on the molecular linkers and phonons in their nuclear environments where electron hopping between the electrodes and the molecular bridge states predominates in the steady state electron transport. The analysis is based on the modified Marcus theory accounting for the lifetime broadening of the bridge's energy levels. We show that the reorganization processes in the environment accompanying electron transport may significantly affect SMJ thermoelectric properties both within and beyond linear transport regime. Specifically, we study the effect of environmental phonons on the electron conductance, the thermopower and charge current induced by the temperature gradient applied across the system.

Large enhancement of thermoelectric effects in multiple quantum dots in a serial configuration due to Coulomb interactions

In the present work we theoretically study Seebeck effect in a set of several quantum dots in a serial configuration coupled to nonmagnetic conducting electrodes. We focus on the combined effect of intra-dot Coulomb interactions between electrons and the number of dots on the thermopower (S) and the thermoelectric figure of merit (ZT) of the considered transport junction within the Coulomb blockade regime. We show that a strong enhancement of the bothSand ZT may occur when the chemical potential of electrodes is situated within the Coulomb gap in the electron transmission spectrum thus indicating a possibility of significant increase of the efficiency of heat-to-electric energy conversion. The enhancement becomes more pronounced when the number of dots increases.

Thermoelectric properties of a double-dot system in serial configuration within the Coulomb blockade regime

In the present work, we theoretically study thermoelectric transport and heat transfer in a junction including a double quantum dot in a serial configuration coupled to nonferromagnetic electrodes. We focus on the electron transport within the Coulomb blockade regime in the limit of strong intradot interactions between electrons. It is shown that under these conditions, characteristics of thermoelectric transport in such systems strongly depend on electron occupation on the dots and on interdot Coulomb interactions. We demonstrate that these factors may lead to a heat current rectification and analyze potentialities of a double-dot in a serial configuration as a heat diod.