Intrinsically Weak Polarization in (4-(Aminomethyl)piperidinium) SnI ₄

(4AMP)SnI 4 (where 4AMP is 4-(Aminomethyl)piperidinium) has recently been identified as a promising lead-free, Sn-based two-dimensional ferroelectric hybrid perovskite. However, the magnitude of its experimentally reported polarization remains controversial. In this work, we perform a detailed symmetry analysis and construct a polarization pathway originating from a manually built centrosymmetric P 2/ c reference structure. Our first-principles calculations reveal that the intrinsic polarization of (4AMP)SnI 4 is approximately 0.97 μC/cm 2, nearly an order of magnitude lower than the values reported experimentally. We attribute this discrepancy to extrinsic effects (leakage current induced by ionic migration) that can falsely enhance ferroelectric hysteresis signals. In addition, we reveal two distinct I – vacancy-mediated ion migration routes and carry out nudged elastic band calculations to evaluate the activation energy barriers of both pathways. The strong frequency dependence observed in experimental polarization hysteresis measurements supports this interpretation, pointing to a dominant contribution from ion diffusion dynamics rather than ferroelectric switching. Our findings highlight the critical importance of distinguishing intrinsic ferroelectric behavior from extrinsic artifacts in hybrid perovskites, especially those exhibiting semiconducting or leaky dielectric properties. This work not only clarifies the polarization mechanism in (4AMP)SnI 4 but also provides a robust theoretical framework for evaluating ferroelectricity in emerging complex and intriguing hybrid perovskite systems.