Finite-size effects on the ferroelectricity in rhombohedral HfO${}_2$

Abstract

In this work we analyze the finite-size effects on the structural properties and on the polarization of the rhombohedral phase of HfO${}_2$ subjected to a biaxial compressive strain. We show how the presence of surface charges affects the polarization, leading to a strong reduction with respect to its bulk value. This reduction can be ascribed to two mechanisms: the coupling between compressive strain and the phase-transition order parameter; the changes in the ferroelectric distortion. We give two alternative explanations of this phenomenon: from an atomistic point of view, analyzing the evolution of the bond lengths, and from a symmetry-analysis point of view, considering the changes in the amplitude of the symmetry-allowed distortions, when a slab configuration is considered. These results are independent on the slab-thickness in the considered range, suggesting the absence of a critical thickness for ferroelectricity in HfO${}_2$, in agreement with the proposed improper nature of hafnia ferroelectricity.

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Cited by in corpus (7)

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• The origin of the ferroelectric-like orthorhombic phase in oxygen-deficient HfO2-y nanoparticles
• Colossal dielectric response of HfxZr1-xO2 nanoparticles
• Resistive switching and charge accumulation in Hf0.5Zr0.5O2 nanoparticles
• Sizes of Ferroelectricity Appearance and Disappearence in Nanosized Hafnia-Zirconia:Landau-type Theory
• Magnetic properties and charge transport mechanisms in oxygen-deficient HfxZr1-xO2-y nanoparticles