Spin-dependent thermoelectric transport through double quantum dots

TL;DR

This paper investigates how spin-dependent interactions and magnetic configurations influence thermoelectric transport in double quantum dots, revealing conditions for high efficiency and spin thermopower.

Contribution

It introduces a detailed analysis of spin-dependent thermoelectric effects in double quantum dots with ferromagnetic electrodes using non-equilibrium Green functions.

Findings

Thermoelectric efficiency peaks in parallel magnetic configuration with small interdot and tunnel couplings.

Efficiency increases with intradot Coulomb interactions and can reach high values at optimal temperatures.

Magnetic fields suppress efficiency but enable pure spin thermopower.

Abstract

We study thermoelectric transport through double quantum dots system with spin-dependent interdot coupling and ferromagnetic electrodes by means of the non-equilibrium Green function in the linear response regime. It is found that the thermoelectric coefficients are strongly dependent on the splitting of interdot coupling, the relative magnetic configurations and the spin polarization of leads. In particular, the thermoelectric efficiency can achieve considerable value in parallel configuration when the effective interdot coupling and tunnel coupling between QDs and the leads for spin-down electrons are small. Moreover, the thermoelectric efficiency increases with the intradot Coulomb interactions increasing and can reach very high value at an appropriate temperature. In the presence of the magnetic field, the spin accumulation in leads strongly suppresses the thermoelectric efficiency and a pure spin thermopower can be obtained.