  Thermoelectric effects through a serial double quantum dot system weakly
coupled to ferromagnetic leads are analyzed. Formal expressions of electrical
conductance, thermal conductance, and thermal coefficient are obtained by means
of Hubbard operators. The results show that although the thermopower is
independent of the polarization of the leads, the figure of merit is reduced by
an increase of polarization. The influences of temperature and interdot
tunneling on the figure of merit are also investigated, and it is observed that
increase of the interdot tunneling strength results in reduction of the figure
of merit. The effect of temperature on the thermal conductance is also
analyzed.
