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arXiv · 2001.09192

Effects of Strain and Film Thickness on the Stability of the Rhombohedral Phase of HfO2

Yuke Zhang·Qiong Yang·Lingling Tao·Evgeny Y. Tsymbal·Vitaly Alexandrov
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Abstract

The discovery of ferroelectric polarization in HfO2-based ultrathin films has spawned a lot of interest due to their potential applications in data storage. Recently, a new R3m rhombohedral phase was proposed to be responsible for the emergence of ferroelectricity in the [111]-oriented Hf0.5Zr0.5O2 thin films, but the fundamental mechanism of ferroelectric polarization in such films remains poorly understood. In this paper, we employ density-functional-theory calculations to investigate structural and polarization properties of the R3m HfO2 phase. We find that the film thickness and in-plane compressive strain effects play a key role in stabilizing the R3m phase leading to robust ferroelectricity of [111]-oriented R3m HfO2.

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Yuke Zhang, Qiong Yang, Lingling Tao, Evgeny Y. Tsymbal, Vitaly Alexandrov. 2020-01-24. Effects of Strain and Film Thickness on the Stability of the Rhombohedral Phase of HfO2. https://doi.org/10.1103/physrevapplied.14.014068

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