Gate tunable spin-charge interconversion in a graphene/ReS$_{2}$ 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 lack of SOC also limits the capacity for manipulating spin current. A key strategy to address this limitation is to induce SOC in graphene via proximity to other two-dimensional (2D) 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 ReS$_\mathrm{2}$, 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 (REE) or the unconventional spin Hall effect (SHE) at the graphene/ReS$_\mathrm{2}$ interface, and the SCI for out-of-plane polarized current to either the conventional SHE in the proximitised graphene, or the unconventional SHE in the bulk of the ReS$_\mathrm{2}$. SCI due to in-plane spin is characterised over a wide range of temperature, up to 300 K and a range of gate voltages.