Organic-inorganic hybrid perovskites with giant piezoelectric responses, exemplified by ${\mathrm{TMCM}\text{−}\mathrm{CdCl}}_3$, represent a promising platform for flexible and environmentally friendly electromechanical materials. However, the microscopic origin of such exceptional performance in this weakly polar system has remained elusive. Here, using deep-learning-assisted large-scale molecular dynamics simulations, we resolve this paradox by reproducing a giant piezoelectric coefficient of $\approx 211\mathrm{pC}/\mathrm{N}$ and demonstrating that it arises from the collective contribution of multiple intrinsic components, particularly the shear component $d_{15}$. This effect does not stem from conventional polarization rotation or phase switching, but instead originates from stochastic 120° in-plane rotational hopping of a small fraction of organic cations. This discrete hopping mechanism is governed by the local ${\mathrm{C}}_3$-symmetric halogen-bonding network between the host framework and the guest cation. The Arrhenius-type temperature dependence of $d_{15}$ further confirms the role of thermally activated dipole hopping. This Letter provides a clear pathway to enhance piezoelectric performance of hybrid materials through rational engineering of host-guest interactions.

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• Ferroelectricity
• Piezoelectricity
• Ferroelectrics
• Piezoelectrics
• Deep learning
• Density functional theory
• Molecular dynamics