Gate tunable spin–charge interconversion in a graphene/ReS2 heterostructure up to room temperature

Graphene is a material with great potential in the field of spintronics, combining good conductivity with low spin–orbit coupling (SOC), which allows for the transport of spin currents over long distances. However, this low SOC also limits the ability to manipulate spin currents. A key strategy to address this limitation is to induce SOC in graphene via proximity to other two-dimensional materials. Such proximity-induced SOC can enable spin–charge interconversion (SCI) in graphene, with potential applications in next-generation logic devices. Here, we place graphene in close proximity to the room-temperature ferroelectric candidate ReS2, inducing SCI for both in-plane and out-of-plane polarized spin current. We attribute the SCI for in-plane polarized current to either the Rashba–Edelstein effect or the unconventional spin Hall effect (SHE) at the graphene/ReS2 interface, and the SCI for out-of-plane polarized current to either the conventional SHE in proximitized graphene or the unconventional SHE in the bulk of the ReS2. SCI due to in-plane spin is characterized over a wide range of temperatures, up to 300 K, and a range of gate voltages.