Quantum miracle: Graphene shows spin currents without any magnets

Researchers at Delft University of Technology have achieved a groundbreaking feat by generating and detecting quantum spin currents in graphene without the use of external magnetic fields. Traditionally, inducing the quantum spin Hall (QSH) effect in graphene required strong magnetic fields, which are impractical for on-chip integration. By placing graphene atop a layered magnetic material called chromium thiophosphate (CrPS₄), the team harnessed magnetic proximity effects to induce spin-orbit coupling and exchange interactions in graphene. This combination opened an energy gap and enabled electrons to flow along graphene’s edges with aligned spins, demonstrating the QSH effect in a magnet-free environment. In addition to observing the QSH effect at cryogenic temperatures, the researchers discovered an anomalous Hall (AH) effect that persisted even at room temperature, where electrons deflect sideways without an external magnetic field. The coexistence of these effects suggests practical pathways for developing ultrathin, spin-based quantum devices. The stable, topologically protected spin currents in graphene could facilitate long-distance