Gate-Tunable Spin Hall Effect in Trilayer Graphene/Group-IV Monochalcogenide van der Waals Heterostructures

Spintronic devices require materials that facilitate effective spin transport, generation, and detection. In this regard, graphene emerges as an ideal candidate for long-distance spin transport owing to its minimal spin-orbit coupling, which, however, limits its capacity for effective spin manipulation. This problem can be overcome by putting spin-orbit coupling materials in close contact with graphene leading to spin-orbit proximity and, consequently, efficient spin-to-charge conversion through mechanisms such as the spin Hall effect. Here, the gate-dependent spin Hall effect in trilayer graphene proximitized with tin sulfide (SnS) is reported and quantified, a group-IV monochalcogenide that has recently been predicted to be a viable alternative to transition-metal dichalcogenides for inducing strong spin-orbit coupling in graphene. The spin Hall angle exhibits a maximum around the charge neutrality point of graphene up to room temperature. The findings expand the library of materials that induce spin-orbit coupling in graphene to a new class, group-IV monochalcogenides, thereby highlighting the potential of 2D materials to pave the way for the development of innovative spin-based devices and future technological applications. The spin Hall effect in trilayer graphene proximitized with tin sulfide (SnS), a group-IV monochalcogenide, is observed with non-local spin precession experiments up to room temperature. The output of the spin-charge interconversion as well as the spin Hall angle is gate tunable and exhibits a maximum when the Fermi level is around the charge neutrality point of the graphene. image