High spin coherency in one-dimensional van der Waals material

One-dimensional van der Waals material, such as InSeI, can be exfoliated to a single wire due to the weak van der Waals interaction between the wires. We experimentally synthesize one-dimensional van der Waals materials with helical structures. Using first-principles calculations and effective Hamiltonian, we report the fixed spin orientation perpendicular to the spin current direction in this material with screw symmetry. The combination of the Rashba and Dresselhaus spin-orbit coupling effect induces the spin splitting of bands with spin-momentum locking and high spin coherency. Our results provide a promising platform for spintronic applications.