Switching between Spin and Orbital Hall Currents in a Single System via Ferrovalley Order.

The spin Hall and orbital Hall effects are fundamental mechanisms for generating transverse spin and orbital currents. However, their intrinsic entanglement via spin-orbit coupling (SOC) has made the generation of pure spin or orbital Hall current a long-standing challenge. Here, we demonstrate a strategy not only to generate but also to reversibly switch between spin and orbital Hall currents within a single material. Combining first-principles calculations with tight-binding modeling, we show that spin-orbital-valley locking, together with external-field-controlled topological band inversion, enables a reversible crossover of Hall transport between spin- and orbital-dominated regimes, even yielding a dominant spin Hall response in weak-SOC systems. Our Letter provides a direct route toward disentangling mixed spin-orbital transport and establishes a versatile platform for the independent control and probing of spin and orbital degrees of freedom.