  The spin-resolved thermoelectric transport properties of correlated nanoscale
junctions, consisting of a quantum dot/molecule asymmetrically coupled to
external ferromagnetic contacts, are studied theoretically in the
far-from-equilibrium regime. One of the leads is assumed to be strongly coupled
to the quantum dot resulting in the development of the Kondo effect. The
spin-dependent current flowing through the system, as well as the
thermoelectric properties, are calculated by performing a perturbation
expansion with respect to the weakly coupled electrode, while the Kondo
correlations are captured accurately by using the numerical renormalization
group method. In particular, we determine the differential and nonequilibrium
Seebeck effects of the considered system in different magnetic configurations
and uncover the crucial role of spin-dependent tunneling on the device
performance. Moreover, by allowing for spin accumulation in the leads, which
gives rise to finite spin bias, we shed light on the behavior of the
nonequilibrium spin Seebeck effect.
