Self detection of Chiral phonon activated spin Seebeck effect in a single crystal of Tellurium

Chiral phonons are quanta of lattice vibration having non-zero angular momentum, offering a new route for coupling spin and heat in chiral solids, such as α-HgS, tellurium, and α-quartz. At thermally equilibrium conditions, the net angular momentum of chiral phonons vanishes unless the chiral material is subject to a nonequilibrium thermal gradient. Previous studies have shown that upon a thermal gradient, the nonzero finite angular momentum of chiral phonons can inject pure spin currents in an adjacent nonmagnetic metallic layer through electron–phonon interactions at chiral material/metal interfaces. Here, we report the intrinsic chiral phonon-activated spin Seebeck effect (CPASS) in elemental tellurium, in which thermally excited chiral phonons create spin polarization within the crystal itself in the absence of an adjacent metallic layer. Unlike prior work, the spin polarization originates inside the chiral lattice rather than in an adjacent metal. This intrinsic CPASS is confirmed through self-detection via the inverse Rashba–Edelstein effect at the Te surface. The observed chirality- and heat-current-dependent responses, supported by chiral phonon calculations, firmly establish the intrinsic nature of the effect.