Mechanically Driven Reversible Polarization Switching in Imprinted BiFeO3 Thin Films

Mechanically driven polarization switching via scanning probe microscopy provides a valuable voltage-free strategy for designing ferroelectric nanodomain structures. However, it is still challenging to realize reversible polarization switching with mechanical forces. Here, the mechanically driven reversible polarization switching observed in imprinted ferroelectric BiFeO3 thin films is reported, i.e., up-to-down switching by a sharp scanning tip and down-to-up switching by a blunt tip. Free energy calculations, phase-field simulations, and piezoresponse force microscopy reveal that reversible mechanical switching arises from the interplay among the flexoelectric effect, the piezoelectric effect, and the internal upward built-in field in BiFeO3 films. This study gains a deeper insight into the mechanism and control of mechanically driven polarization switching, and provides guidance for exploring potential ferroelectric-based electro-mechanical microelectronics.

Automated summary

Mechanically driven reversible polarization switching has been achieved in imprinted ferroelectric BiFeO3 thin films, allowing for the design of ferroelectric nanodomain structures without the need for voltage application. This reversible switching is enabled by the flexoelectric effect, piezoelectric effect, and internal upward built-in field in the BiFeO3 films. The study provides valuable insights into the mechanism and control of mechanically driven polarization switching, and offers guidance for the development of ferroelectric-based electro-mechanical microelectronics.