How to control Spin-Seebeck current in a metal-quantum dot-magnetic insulator junction

TL;DR

This paper proposes a controllable spin-Seebeck device using a quantum dot between a metal and magnetic insulator, demonstrating significant current enhancement via energy level tuning and correlation effects, with potential for spin caloritronic applications.

Contribution

Introducing a quantum dot into a spin-Seebeck device to enable control over the current through gate voltage tuning and correlation effects, advancing spin caloritronic device design.

Findings

Spin-Seebeck current increases when QD energy level is near the Fermi level.

Quantum resonance enhances spin flipping and current.

Device can function as a thermovoltaic transistor.

Abstract

The control of the spin-Seebeck current is still a challenging task for the development of spin caloritronic devices. Here, we construct a spin-Seebeck device by inserting a strongly correlated quantum dot (QD) between the metal lead and magnetic insulator. Using the slave-particle approach and non-crossing approximation, we find that the spin-Seebeck effect increases significantly when the energy level of the QD locates near the Fermi level of the metal lead due to the enhancement of spin flipping and occurrences of quantum resonance. Since this can be easily realized by applying a gate voltage in experiments, the spin-Seebeck device proposed here can also work as a thermovoltaic transistor. Moreover, the optimal correlation strength and the energy level position of the QD are discussed to maximize the spin-Seebeck current as required for applications in controllable spin caloritronic devices.