Spintronics-based mesoscopic heat engine

We consider a nanowire suspended between two spin-polarized leads and subjected to a nonuniform magnetic field. We show that a temperature drop between the leads can significantly affect the nanowire dynamics. In particular, it is demonstrated that, under certain conditions, the stationary distribution of the mechanical subsystem has a Boltzmann form with an effective temperature, which is lower than the temperature of the ``cold'' lead; this seems rather counterintuitive. We also find that a change in the direction of the temperature gradient can result in the generation of mechanical vibrations rather than the heating of the mechanical subsystem.