Ferroelectric Spin-Orbit Valve Effect

In ferroelectric (FE) semiconductors with strong spin-orbit coupling, the electron's spin direction is locked to its momentum by an intrinsic spin-orbit field (SOF) switchable by ferroelectric polarization. This provides a promising platform for novel nonvolatile spintronic devices. Here, we propose exploiting the switchable SOF to realize a FE spin-orbit valve (FE-SOV), where two FE semiconductors are separated by a thin barrier layer. Because of the locking between the SOF and polarization direction, the conductance of the FE-SOV strongly depends on the relative orientation of polarization of the two FE semiconductors. Using a tight-binding model and density functional theory calculations for FE-SOVs based on twodimensional FE SnTe and Bi, we demonstrate a giant FE-SOV effect that is characterized by the conductance change of several orders in magnitude. Our work enriches spin-orbit physics of ferroelectrics and proposes a new type of all-electric control of a nonvolatile spin-orbitronic device, which holds promise for future electronic and memory applications.