Ultrafast Ferroelectric Domain Switching Induced by Nano‐Second Strain‐Pulse

Surface Effect of Thickness-Dependent Polarization and Domain Evolution in BiFeO3 Epitaxial Ultrathin Films

With the trend of device miniaturization, ultrathin ferroelectric films are gaining more and more attention. However, understanding ferroelectricity in this nanoscale context remains a formidable challenge, primarily due to the heightened relevance of surface effects, which often leads to the loss of net polarization. Here, the influence of surface effects on the polarization as a function of thickness in ultrathin BiFeO3 films is investigated using phase-field simulations. The findings reveal a notable increase in ferroelectric polarization with increasing thickness, with a particularly discernible change occurring below the 10 nm threshold. Upon accounting for surface effects, the polarization is marginally lower than the case without such considerations, with the disparity becoming more pronounced at smaller thicknesses. Moreover, the hysteresis loop and butterfly loop of the ultrathin film were simulated, demonstrating that the ferroelectric properties of films remain robust even down to a thickness of 5 nm. Our investigations provide valuable insights into the significance of ferroelectric thin films in device miniaturization.

Antiferroelectric Phase Diagram Enhancing Energy-Storage Performance by Phase-Field Simulations

Antiferroelectric materials have shown potential applications in energy storage. However, controlling and improving the energy-storage performance in antiferroelectric remain challenging. Here, a domain structure and energy-storage performance diagram for Pb(Zr_1-xTi_x)O₃ (x ≤ 0.1) single crystal are investigated via phase-field simulations. Controlling the ratio of domain wall coefficients λ and g can tune the periodicities of the antiferroelectric stripe domain and generate a complicated topological domain. By decreasing the antiferroelectric domain periodicity, one can achieve high recoverable energy-storage density (W_rec = 30.24 J/cm³) with an efficiency of 80.9%. In addition, Pb(Zr_1-xTi_x)O₃ (x ≤ 0.1) thin-film system has also been investigated. Positive equiaxial misfit strain significantly enhances recoverable energy-storage density up to 21.96 J/cm³ with an efficiency of 84.9%. Our results offer another train of thought to tune antiferroelectric domain structure, which provides the idea to design high-energy-density materials in experiments.