Polarization-driven enhancement of the thermal switch ratio arising from strong four-phonon scattering in bilayer α-In 2 Se 3

) increases from 1.3 to 1.9 at 300 K. Furthermore, with increasing temperature, the coherent contribution to the thermal conductivity gradually increases. These results explain the underlying mechanisms of thermal transport in bilayer ferroelectric materials with polarization, and provide new insights for the design of nanoscale thermal management devices.