Electrode-tunable nonlocal charge to spin conversion in WSe$_2$-intercalated bilayer graphene

Abstract

We show that intercalating a WSe$_2$ monolayer into bilayer graphene mediates wavefunction hybridization of the two graphene layers at the Fermi level. These delocalized states entangle both graphene layers, creating a synthetic bilayer graphene with interlayer coupling comparable to the proximity-induced spin-orbit interaction. By analyzing transport properties of a four-terminal device, we demonstrate equal entangled parallel charge currents in both graphene layers, allowing us to unlock the hidden Rashba states via layer-selective chirality manifested in opposite-signed local Rashba-Edelstein signals. We also show nonlocal Rashba-Edelstein and spin Hall effects activated in one graphene layer when a charge current is driven in a spatially adjacent graphene layer. This effect is robust to the twist angle modulation between graphene and WSe$_2$, and to the applied electric field, suggesting its durability.