  We propose a two-terminal spin-orbit interferometer with a hot molecule
inserted in one of its arms to generate pure spin currents. Local heating is
achieved by coupling the vibrational modes of the molecule to a third
(phononic) reservoir. We show that this spin calorimetric effect is due to the
combined influence of spin-dependent wave interference and inelastic
scattering. Remarkably, the device converts heat flow into spin-polarized
current even without applying any voltage or temperature difference to the
electronic terminals.
