β-angle Distortion Stabilized Antiferroelectricity in Engineered ZrO₂-LSMO Laminate Structure.

Abstract

Fluorite-structured thin films have drawn significant attention for their ferro-/anti-ferroelectric properties, due to their scale-free nature and excellent compatibility with complementary metal-oxide-semiconductor (CMOS) technology. While epitaxial ferroelectric fluorite films have advanced mechanistic understanding and performance optimization, stabilizing antiferroelectricity in epitaxial fluorites remains challenging, limiting both fundamental insights and device potential. Here, stabilization of the antiferroelectric Pbca phase in ZrO₂-LSMO laminate structures grown on LSAT (110) substrates is reported, with a reversible and non-volatile transition between Pbca and Pca2₁ phases. The discontinuous epitaxial interfaces introduced by LSMO intercalation generate a high-density of edge and screw dislocations, which impose shear strains and induce β-angle distortion in ZrO₂. Systematic lattice distortion analysis, supported by density functional theory, reveals the critical role of β-angle distortion in stabilizing the Pbca phase and governing its phase transition. A phase stability map is further established for ZrO₂ epitaxial films under varying strain states. This work bridges a long-standing knowledge gap regarding antiferroelectricity in epitaxial fluorite systems and demonstrates β-angle distortion as a tunable design parameter for antiferroelectric properties, which offers new routes to optimize fluorite oxide-based information and energy storage devices.