Subsecond optically controlled domain switching in freestanding ferroelectric BaTiO₃ membrane

The quest to develop energy-efficient and fast optoelectronic control of memory devices is essential. In this respect, ferroelectric materials are gaining tremendous importance in information and communication technology. Here, we demonstrate light-controlled polarisation switching on a subsecond timescale ( <500 ms) in a freestanding BaTiO₃ membrane, which is nearly 1200 times faster than the previously reported response using a BaTiO₃ thin film. We reveal the potential of optically controlled computing by demonstrating the associated resistance change in the membrane as a result of the polarisation reversal induced by illumination. By combining theoretical and experimental studies, we demonstrate that the imprint effect coupled with the reduced energy barrier of domain wall motion influences the optically controlled domain switching response in the membrane. It is established that the fast domain switching response in the freestanding film compared to the clamped film is attributed to the removal of substrate-induced strain and the subsequent increase in domain wall velocity. Additionally, ferroelectric fatigue behaviour is not observed in our system even after 75 electrical and optical cycles, demonstrating the robustness of the observed phenomenon. Our work provides a step forward towards wireless sensing and dual optical and electronic control for computing.