Interface Induced Ferroelectricity in Designed CeO ₂ , HfO ₂ , ZrO ₂ and YSZ Based Superlattice Heterostructures

ABSTRACT The stabilization of ferroelectricity in non‐polar oxides remain a key challenge in the design of next‐generation functional materials, as existing approaches typically rely on chemical substitution, or metastable phases. Here, we report a universal and experimentally realizable route to emergent ferroelectricity based on interfacial symmetry frustration in oxide superlattices composed of dissimilar crystal symmetries. We design superlattice thin films heterostructures integrating cubic (CeO 2 , YSZ) and monoclinic (HfO 2 , ZrO 2 ) oxide layers showing spontaneous polarization that are non‐polar in their bulk phases. High‐resolution structural characterization confirms coherent heterointerfaces, while piezoresponse force microscopy and macroscopic electrical measurements establish switchable polarization. First‐principles calculations reveal that the crystalline symmetry mismatch across the interfaces breaks inversion symmetry and induces polar distortions through interface‐driven structural frustration, giving rise to emergent ferroelectricity without the need for chemical modification or metastable phase control. Our findings identify interfacial crystalline symmetry incompatibility as a general design principle for engineering ferroelectricity in superlattice heterostructures, opening new pathways for functional oxide electronics beyond conventional ferroelectric material systems.