Scientists at TU Delft have unlocked a key quantum effect in The scientists from the Van der Zant lab were able to bypass the need for external fields by layering the graphene on top of a magnetic material: CrPS₄. This magnetic layer significantly altered the graphene’s electronic properties, giving rise to the QSH effect in graphene. Ghiasi: “We observed that the spin transport in graphene gets modified by the neighbouring CrPS4 such that the flow of electrons in graphene becomes dependent on the electrons’ spin direction.” The quantum spin currents that the scientists detect in the graphene-CrPS4 stack are ‘topologically’ protected, implying that the spin signal travels stays intact over tens of micrometres long distances without losing the spin information in the circuit. “These topologically-protected spin currents are robust against disorders and defects, making them reliable even in imperfect conditions,” Ghiasi says. Preserving spin signal without any loss of information is vital for building spintronic circuits. This discovery paves the way toward ultrathin, graphene-based spintronic circuits, promising advancements in next-generation memory and computing technologies. The observed spin currents in graphene offer a powerful new route for efficient and coherent transfer of quantum information through electron spins. These robust spintronic devices could serve as essential building blocks in quantum computing, seamlessly linking qubits together within quantum circuits. Reference: “Quantum spin Hall effect in magnetic graphene” by Talieh S. Ghiasi, Davit Petrosyan, Josep Ingla-Aynés, Tristan Bras, Kenji Watanabe, Takashi Taniguchi, Samuel Mañas-Valero, Eugenio Coronado, Klaus Zollner, Jaroslav Fabian, Philip Kim and Herre S. J. van der Zant, 24 June 2025, DOI: 10.1038/s41467-025-60377-1 Never miss a breakthrough: Join the SciTechDaily newsletter.
Topologically Protected Spin Signals
Path to Ultra-Thin Quantum Circuits
