Spin-Valve Effect for Spin-Polarized Surface States in Topological Semimetals

We experimentally investigate magnetoresistance of a single GeTe–Ni junction between the $$\alpha $$ -GeTe topological semimetal and thick nickel film at room and liquid helium temperatures. For the magnetic field parallel to the junction plane, we demonstrate characteristic spin-valve hysteresis with mirrored differential resistance $$dV{\text{/}}dI$$ peaks even at room temperature. In contrast, for normal magnetic fields spin-valve effect appears only at low temperatures. From the magnetic field anisotropy, observation of the similar effect for another topological semimetal Cd 3 As 2 , and strictly flat $$dV{\text{/}}dI(H)$$ magnetoresistance curves for the reference GeTe–Au junction, we connect the observed spin-valve effect with the spin-dependent scattering between the spin textures in the topological surface states and the ferromagnetic nickel electrode. For the topological semimetal $$\alpha $$ -GeTe, room-temperature spin-valve effect allows efficient spin-to-charge conversion even at ambient conditions.