Spin-current Seebeck effect in quantum dot systems

TL;DR

This paper explores the spin-current Seebeck effect in quantum dot systems, showing how it can detect polarization states and be enhanced by Coulomb interactions or magnetic fields, with potential for sensitive spin state monitoring.

Contribution

It introduces the concept of spin-current Seebeck effect in quantum dots and demonstrates its sensitivity to polarization states and how Coulomb interactions enhance the effect.

Findings

Spin-current Seebeck coefficient is sensitive to QD polarization states.

Coulomb interaction can enhance the Seebeck coefficient by up to 80 times.

External magnetic fields can induce large Seebeck effects even without Coulomb interactions.

Abstract

We first bring up the concept of spin-current Seebeck effect based on a recent experiment [Nat. Phys. {\bf 8}, 313 (2012)], and investigate the spin-current Seebeck effect in quantum dot (QD) systems. Our results show that the spin-current Seebeck coefficient $S$ is sensitive to different polarization states of QD, and therefore can be used to detect the polarization state of QD and monitor the transitions between different polarization states of QD. The intradot Coulomb interaction can greatly enhance the $S$ due to the stronger polarization of QD. By using the parameters for a typical QD, we demonstrate that the maximum $S$ can be enhanced by a factor of 80. On the other hand, for a QD whose Coulomb interaction is negligible, we show that one can still obtain a large $S$ by applying an external magnetic field.