Tuning proximity spin-orbit coupling in graphene / NbSe 2 heterostructures via twist angle

We investigate the effect of the twist angle on the proximity spin -orbit coupling (SOC) in graphene / NbSe 2 heterostructures from first principles. The low -energy Dirac bands of several different commensurate twisted supercells are fitted to a model Hamiltonian, allowing us to study the twist -angle dependency of the SOC in detail. We predict that the magnitude of the Rashba SOC can triple, when going from 0 = 0 degrees to 0 = 30 degrees twist angle. Furthermore, at a twist angle of 0 approximate to 23 degrees the in -plane spin texture acquires a large radial component, corresponding to a Rashba angle of up to (I) = 25 degrees . The twist -angle dependence of the extracted proximity SOC is explained by analyzing the orbital decomposition of the Dirac states to reveal with which NbSe 2 bands they hybridize strongest. Finally, we employ a Kubo formula to evaluate the efficiency of conventional and unconventional charge -to -spin conversion in the studied heterostructures.