Spin-orbit driven spin depolarization in the ferromagnetic Weyl semimetal Co₃Sn₂S₂

Co₃Sn₂S₂ has recently emerged as a ferromagnetic Weyl semimetal. Previous experiments and theoretical investigations of the band structure have provided an indication of the possibility of half-metallicity in this compound. However, our spectroscopic investigations have shown that a spin-polarized super-current flows through a Nb/Co₃Sn₂S₂ point contact with a large Andreev reflection indicating a huge deviation from half-metallic character. In fact, we have observed a 50% spin polarization at the Fermi level. Theoretical calculation of the electronic density of states with inclusion of spin-orbit coupling showed that this deviation stems from a spin depolarizing effect near the Fermi energy. Additionally, the calculations revealed a particle-hole asymmetry that explains our experimental observation of asymmetric Andreev reflection spectra.