Spin thermoelectric effects in a double quantum dot embedded in an Aharonov–Bohm ring coupled to nonmagnetic leads

Abstract

Spin thermoelectric effects in a Rashba double quantum dot (QD) embedded in one arm of an Aharonov–Bohm (AB) ring are investigated theoretically in the linear response regime with the use of Green's function method. We found that by applying an external thermal bias to QD-1, the spin Seebeck effect can be induced due to the presence of Heisenberg exchange coupling between QD-1 and QD-2. A high spin thermopower with a maximum as large as 1.5kB/e and spin figure of merit with a maximum as large as 1.4 can be obtained with the coaction of exchange coupling and interference effect, but without the need for any extra magnetic field or ferromagnetic electrodes. In addition, the spin thermoelectric effect can be manipulated effectively by the spin–orbit interaction and the magnetic flux. The results indicate that such a double dot ring system may lead to potential applications in spin thermoelectric devices.