Spin thermoelectric transport in a four-quantum-dot ring: Influence of quantum dots magnetization

Non-equilibrium Green's function method is applied to study the spin thermoelectric effects in a four-quantum-dot ring with two of the quantum dots magnetized. The influence of magnetic configuration on the spin thermoelectric transport through the system is investigated. In some magnetic configurations, a significant spin Seebeck coefficient S-s can be generated with the variation of the quantum dot (QD) energy level. Appropriately tuning the QD energy level can let the present device work as a pure spin-up (spin-down) or a pure-spin-current thermal generator. The combined effect of the magnetization and magnetic flux (or Rashba spin-orbit coupling) is also investigated. Finally, the charge figure of merit Z(c)T and spin figure of merit Z(s)T are evaluated, it is found that the magnitude of the spin figure of merit can be comparable to that of the charge counterpart.