Bipolar thermoelectric effect in a srially coupled quantum dot system

TL;DR

This paper theoretically investigates the bipolar thermoelectric effect in serially coupled quantum dot systems, revealing sign changes in the Seebeck coefficient due to electron-hole tunneling competition and oscillatory behavior in parallel configurations.

Contribution

It introduces a theoretical analysis of bipolar thermoelectric effects in coupled quantum dots, highlighting the sign change of the Seebeck coefficient with temperature and oscillatory behavior in parallel systems.

Findings

Sign change in Seebeck coefficient with temperature due to bipolar tunneling.

Oscillatory behavior of Seebeck coefficient in parallel quantum dot systems.

Potential to control thermoelectric current direction via temperature variation.

Abstract

The Seebeck coefficient (S) of a serially coupled quantum dot (SCQD) junction system is theoretically studied via a two-level Anderson model. A change of sign in S with respect to temperature is found, which arises from the competition between tunneling currents due to electrons and holes (i.e, bipolar tunneling effect). The change of sign in S implies that one can vary the equilibrium temperature to produce thermoelectric current in either the forward or reverse direction, leading to a bipolar thermoelectric effect. For the case of two parallel SCQDs, we also observe the oscillatory behavior of S with respect to temperature.