Each quintuple layer (Se–In–Se–In–Se) carries an out-of-plane polarization set by the central Se plane. A gate field larger than the coercive field drives that plane to its other stable site, flipping P — and the state remains once the field is removed.
InSe (outer)Se (central, switchable)Applied gate field EMaterial polarization P
Inside the channel · 3 quintuple layers
Ferroelectric-semiconductor FET
Polarization hysteresis
Molecular beam epitaxy
P ↑
Drag VG past ±Vc to switch. Below the coercive field the blue field arrows grow but the pink P arrows hold — return to 0 V and the FET still reads the stored state (non-volatile). Values are illustrative.