The research team from the School of Science at Westlake University published a study titled “Giant Reversible Piezoelectricity from Symmetry-Governed Stochastic Dipole Hopping” in Physical Review Letters. The work, led by Dr. Shi Liu, investigates the microscopic origins of the giant piezoelectric effect observed in the organic-inorganic hybrid perovskite TMCM-CdCl₃.

By employing deep-learning-assisted large-scale molecular dynamics simulations, the researchers addressed the paradox of how a weakly polar material achieves a piezoelectric response comparable to traditional inorganic ceramics. The study clarifies that the macroscopic longitudinal response measured in experiments is primarily dominated by the intrinsic shear component. Furthermore, the underlying mechanism is distinct from the previously proposed models of polarization rotation or phase switching. Instead, the simulations reveal that the giant response arises from organic cations anchored by halogen bonds, which exhibit stochastic 120-degree in-plane rotational hopping under shear stress. This research provides a clearer physical picture of electromechanical coupling in molecular ferroelectrics.

Denan Li, a Ph.D. candidate at Westlake University, is the first author of the paper. Prof. Shi Liu (Westlake University) is the corresponding author. Prof. Yi Zhang (Zhejiang Normal University) and Haofei Ni (Zhejiang Normal University) also made important contributions to this work.