Stacking selected polarization switching and phase transition in vdW ferroelectric α-In2Se3 junction devices.

The structure and dynamics of ferroelectric domain walls are essential for polarization switching in ferroelectrics, which remains relatively unexplored in two-dimensional ferroelectric α-In₂Se₃. Interlayer interactions engineering via selecting the stacking order in two-dimensional materials allows modulation of ferroelectric properties. Here, we report stacking-dependent ferroelectric domain walls in 2H and 3R stacked α-In₂Se₃, elucidating the resistance switching mechanism in ferroelectric semiconductor-metal junction devices. In 3R α-In₂Se₃, the in-plane movement of out-of-plane ferroelectric domain walls yield a large hysteresis window. Conversely, 2H α-In₂Se₃ devices favor in-plane domain walls and out-of-plane domain wall motion, producing a small hysteresis window. High electric fields induce a ferro-paraelectric phase transition of In₂Se₃, where 3R In₂Se₃ reaches the transition through intralayer atomic gliding, while 2H In₂Se₃ undergoes a complex process comprising intralayer bond dissociation and interlayer bond reconstruction. Our findings demonstrate tunable ferroelectric properties via stacking configurations, offering an expanded dimension for material engineering in ferroelectric devices. The lack of information on the ferroelectric domain walls motion characteristics in α-In₂Se₃ hampers the understanding of the ferroelectric semiconductor junction device mechanism. Here, the authors report that the stacking order of van der Waals α-In₂Se₃ determines its ferroelectric domain wall type and phase transition pathway. [ABSTRACT FROM AUTHOR]