Current-induced magnetization switching at charge-transferred interface between topological insulator (Bi,Sb)₂Te₃ and van der Waals ferromagnet Fe₃GeTe₂

Ferromagnetic two-dimensional van der Waals materials attract enormous interest as a platform to explore spin-related quantum phenomena, especially in conjunction with other quantum materials. Topological insulator is one such candidate to form the junction, because the spin-polarized nature of the surface or interface Dirac states enables the highly efficient spin-charge conversion. Here, we report the current-driven magnetization switching in the bilayer film of a van der Waals ferromagnetic semimetal Fe₃GeTe₂ (FGT) and a topological insulator (Bi_1−xSb_x)₂Te₃ (BST). We observed the current-induced magnetization switching via the Edelstein effect in a wide temperature range, whose threshold current density is as small as that reported for the heterostructure of FGT with a Pt layer. By analyzing the transport properties in heterostructures with different Fermi level (E_F) positions in the BST layer, we found that the E_F position of the charge-transferred interface Dirac states causes the significant variation of the threshold current density with a Bi/Sb ratio. The present result may promise spintronic phenomena in heterostructures of 2D van der Waals ferromagnets with topological insulators/semimetals.