Boosting Inversion Symmetry Breaking in Epitaxial Tetragonal ZrO2 Via Atomic Layer Deposition

High Resolution Image Download MS PowerPoint Slide The stabilization of intermediate polar phases in fluorite-structured oxides is critical for advancing ferroelectric and antiferroelectric applications. Here, we report the stabilization of epitaxial polar tetragonal (T) ZrO 2 . Epitaxial Hf x Zr 1– x O 2 thin films (x = 1, 0.75, 0.5, 0.25, and 0) are synthesized on (001) yttria-stabilized zirconia substrates via atomic layer deposition. The emergence of the unprecedented polar T-ZrO 2 phase deviates from the expected phase transition from nonpolar HfO 2 through ferroelectric Hf 0.5 Zr 0.5 O 2 to antiferroelectric Zr-rich Hf x Zr 1– x O 2 . Second harmonic generation measurements reveal unexpected inversion symmetry breaking in T-phase ZrO 2 . High-resolution 4D-scanning transmission electron microscopy further confirms the presence of electric dipoles originating from off-centered oxyge…