Charge to spin conversion in van der Waals metal NbSe2

Abstract

Quantum materials with a large charge current-induced spin polarization are promising for next-generation all-electrical spintronic science and technology. Van der Waals metals with high spin–orbit coupling and spin textures have attracted significant attention for an efficient charge-to-spin conversion process. Here, we demonstrate the electrical generation of spin polarization in NbSe2 up to room temperature. Characterization of NbSe2 shows superconducting transition temperature, Tc ∼ 7 K. To probe the current-induced spin polarization in NbSe2, we used a graphene-based non-local spin-valve device, where the spin-polarization in NbSe2 is efficiently injected and detected using non-local spin-switch and Hanle spin precession measurements. A significantly higher charge-spin conversion in NbSe2 is observed at a lower temperature. Systematic measurements provide the possible origins of the spin polarization to be predominantly due to the spin Hall effect or Rashba–Edelstein effect in NbSe2, considering different symmetry-allowed charge-spin conversion processes.