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  • Open Access

Soft mode-driven reduction of switching energy barriers in fluorite ferroelectric

Jinhyeong Jo1,*, Pawan Kumar1,*, and Jun Hee Lee1,2,†

  • 1Department of Energy Engineering, School of Energy and Chemical Engineering, UNIST, Ulsan 44919, Republic of Korea
  • 2Graduate School of Semiconductor Materials and Devices Engineering, UNIST, Ulsan 44919, Republic of Korea

  • *These authors contributed equally to this work.
  • †Contact author: junhee@unist.ac.kr
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Phys. Rev. Research 7, 043046 – Published 14 October, 2025

DOI: https://doi.org/10.1103/kkk8-s3lk

Abstract

The low coercive field (Ec) is highly desirable for developing efficient and durable ferroelectric-based devices. However, fluorite ferroelectrics such as HfO2 and ZrO2, which are attracting significant attention as next-generation semiconductor materials due to their compatibility with complementary metal-oxide-semiconductor technology and robust ferroelectric properties, exhibit a significantly high Ec, severely limiting their application in memory devices. Here, using group theory and first-principles simulations, we reveal that phonon engineering can induce a new soft mode in the polar Pca21 phase of HfO2 and ZrO2. This mode dominates the intermediate transition state during polarization switching and drastically reduces the energy barriers for both homogeneous switching and the uniquely observed local switching, which enables ultrahigh memory density. Furthermore, the discovery of a ternary state during local switching points to the possibility of implementing ternary logic at the material level. Our findings introduce a new pathway to lowering Ec in fluorite ferroelectrics by exploiting intrinsic lattice dynamics, offering an alternative to conventional strategies such as doping or defect engineering, and open a promising direction for future material design.

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Phys. Rev. Research 7, 043046– Published 14 October, 2025
  • Received 5 May 2025
  • Accepted 15 September 2025
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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