Spin Seebeck Effect in a Multiple Quantum Dot Molecule with Spin-Dependent Interdot Coupling

We study the spin Seebeck effect in a circularly connected triple quantum dot (TQD) structure taking the spin-dependent interdot coupling and magnetic flux into consideration. Particular attention is paid on the generation and manipulation of the 100% spin-polarized and pure spin thermopowers, which denote the arisen spin voltage in response of an infinitely small temperature gradient applied across the system. This can be realized by adjusting the peaks' positions in the spin-up and spin-down thermopowers with the help of the spin polarization of the interdot couplings. At low temperature, a large value of pure spin thermopower is obtained even under very weak spin polarization of the interdot coupling. Strong spin polarization of it is favorable for 100% spin-polarized thermopower whose magnitude can reach as large as that of the charge one. We also find that a sign change of the considered two quantities can be realized by adjusting the magnetic flux penetrating through the TQDs. The present results could be useful in designing high-efficiency pure spin energy conversion and spin filter devices.