Unravelling Rashba-Dresselhaus Splitting Assisted Magneto-Photoelectrochemical Water Splitting in Asymmetric MoSSe-GaN Heterostructures.

Among two-dimensional (2D) materials, asymmetric Janus structures (MoSSe, WSSe) have many exciting properties, such as out-of-plane piezoelectricity, spatial isolation of charge carriers, and strong spin-orbit coupling (SOC), resulting in a significant Rashba effect. However, the experimental validation to utilize SOC along with advanced optical properties for catalytic applications remains unexplored. Herein, for the first time, we demonstrate a proof-of-concept for spin-manipulated photo-electrochemical water splitting using Janus MoSSe/GaN heterostructures under an external low magnetic field. Further, the activation with delaminated 2D-MXene (Ti 3 C 2 T x /MoSSe/GaN) for efficient electron channeling manifests ∼1.37 times photocurrent enhancement and ∼1.50-fold enhancement in product (H 2 /O 2 ) formation under a low applied magnetic field (0.4 T). The external magnetic field supports spin manipulation even under unpolarized light by a spin-to-charge conversion in Janus MoSSe/GaN heterostructures. Density functional theory simulations were performed to understand the role of the Rashba-Dresselhaus effect for efficient charge transport.