Abstract
Hafnia-based ferroelectrics hold significant promise for next-generation non-volatile memory. However, their functional properties are critically limited by uncontrollable phase transitions due to the poorly understood atomistic mechanisms driving specific transformations. Here, using single-crystalline HfO2-based superlattice films as the prototype system, we propose an asynchronous sublattice distortion mechanism underlying the complex phase transitions in HfO2-based materials. Aberration-corrected transmission electron microscopy reveals that sublattice preferential distortion behaviors trigger various phase transitions among orthorhombic, tetragonal and monoclinic phases, processes governed by the direction of orthorhombic phase. Critically, the complex lattice distortion pathways underlying the orthorhombic-to-monoclinic transition are elucidated, revealing their fundamental dependence on the monoclinic projection direction. Furthermore, polar-antipolar transition within the orthorhombic phase requires only oxygen sub-lattice dipole-order reversal, enabling polarization flipping. This work systematically clarifies the core mechanisms of structural phase transitions in HfO2-based films, resolving previous controversies and providing a guidance for designing high-performance HfO2-based electronic devices.
Similar content being viewed by others
Data availability
The data sets generated and analyzed during the current study are available from the corresponding author on reasonable request.
References
Boscke, T. S., Muller, J., Brauhaus, D., Schroder, U. & Bottger, U. Ferroelectricity in hafnium oxide thin films. Appl. Phys. Lett. 99, 102903 (2011).
Cheema, S. S. et al. Enhanced ferroelectricity in ultrathin films grown directly on silicon. Nature 580, 478–482 (2020).
Lee, H.-J. et al. Scale-free ferroelectricity induced by flat phonon bands in HfO2. Science 369, 1343–1347 (2020).
Ma, L. et al. Ultrahigh oxygen ion mobility in ferroelectric hafnia. Phys. Rev. Lett. 131, 256801 (2023).
Wu, Y. et al. Unconventional polarization-switching mechanism in (Hf, Zr)O2 ferroelectrics and its implications. Phys. Rev. Lett. 131, 226802 (2023).
Tang, Y. L. et al. Observation of a periodic array of flux-closure quadrants in strained ferroelectric PbTiO3 films. Science 348, 547–551 (2015).
Yadav, A. K. et al. Observation of polar vortices in oxide superlattices. Nature 530, 198–201 (2016).
Geng, W. R. et al. Dipolar wavevector interference induces a polar skyrmion lattice in strained BiFeO3 films. Nat. Nanotechnol. 20, 366–373 (2025).
Geng, W. R. et al. Observation of multi-order polar radial vortices and their topological transition. Nat. Commun. 16, 2804 (2025).
Ma, L.-Y. & Liu, S. Structural polymorphism kinetics promoted by charged oxygen vacancies in HfO2. Phys. Rev. Lett. 130, 8 (2023).
Geng, W. R. et al. A stable monoclinic variant and resultant robust ferroelectricity in single-crystalline hafnia-based films. Nat. Commun. 16, 8842 (2025).
Huan, T. D., Sharma, V., Rossetti, G. A. & Ramprasad, R. Pathways towards ferroelectricity in hafnia. Phys. Rev. B 90, 064111 (2014).
Zhao, D., Chen, Z., & Liao, X. Microstructural evolution and ferroelectricity in HfO2 films. Microstructures2, 2022007 (2022).
Li, X. et al. Polarization switching and correlated phase transitions in fluorite-structure ZrO2 nanocrystals. Adv. Mater. 35, 1 (2023).
Li, X. et al. Ferroelastically protected reversible orthorhombic to monoclinic-like phase transition in ZrO2 nanocrystals. Nat. Mater. 8, 23 (2024).
Müller, J. et al. Ferroelectricity in simple binary ZrO2 and HfO2. Nano Lett 12, 4318–4323 (2012).
Wang, Y. et al. A stable rhombohedral phase in ferroelectric Hf(Zr)1+xO2 capacitor with ultralow coercive field. Science 381, 558–563 (2023).
Cheema, S. S. et al. Emergent ferroelectricity in subnanometer binary oxide films on silicon. Science 376, 648–652 (2022).
Estandía, S. et al. Engineering ferroelectric Hf0.5Zr0.5O2 thin films by epitaxial stress. ACS Appl. Electron. Mater. 1, 1449–1457 (2019).
Yun, Y. et al. Intrinsic ferroelectricity in Y-doped HfO2 thin films. Nat. Mater. 21, 903–909 (2022).
Kelley, K. P. et al. Ferroelectricity in hafnia controlled via surface electrochemical state. Nat. Mater. 22, 1144–1151 (2023).
Kang, S. et al. Highly enhanced ferroelectricity in HfO2-based ferroelectric thin film by light ion bombardment. Science 376, 731–738 (2022).
Shi, S. et al. Interface-engineered ferroelectricity of epitaxial Hf0.5Zr0.5O2 thin films. Nat. Commun. 14, 1780 (2023).
Wang, S. et al. Unlocking the phase evolution of the hidden non-polar to ferroelectric transition in HfO2-based bulk crystals. Nat. Commun. 16, 3745 (2025).
Cheng, Y. et al. Reversible transition between the polar and antipolar phases and its implications for wake-up and fatigue in HfO2-based ferroelectric thin film. Nat. Commun. 13, 1–8 (2022).
Grimley, E. et al. Structural changes underlying field-cycling phenomena in ferroelectric HfO2 thin films. Adv. Electron. Mater. 2, 1600173 (2016).
Fan, Y. et al. Hidden structural phase transition-assisted ferroelectric domain orientation engineering in Hf0.5Zr0.5O2 films. Nat. Commun. 16, 4232 (2025).
Solomon, A. P. et al. Atomic-scale structure of ZrO2: Formation of metastable polymorphs. Sci. Adv. 11, eadq5943 (2025).
Cheema, S. S. et al. Ultrathin ferroic HfO2-ZrO2 superlattice gate stack for advanced transistors. Nature 604, 65–71 (2022).
Li, J. et al. Enhancing ferroelectric stability: wide-range of adaptive control in epitaxial HfO2/ZrO2 superlattices. Nat. Commun. 16, 6417 (2025).
Ma, J. Y. et al. Real-time observation of phase coexistence and a1/a2 to flux-closure domain transformation in ferroelectric films. Acta Mater 193, 311–317 (2020).
Chen, Z., Wang, X., Ringer, S. P. & Liao, X. Manipulation of nanoscale domain switching using an electron beam with omnidirectional electric field distribution. Phys. Rev. Lett. 117, 027601 (2016).
Wei, J. et al. Direct imaging of atomistic grain boundary migration. Nat. Mater. 20, 951–955 (2021).
Reyes-Lillo, S. E., Garrity, K. F. & Rabe, K. M. Antiferroelectricity in thin-film ZrO2 from first principles. Phys. Rev. B 90, 140103 (2014).
Xu, X. et al. Kinetically stabilized ferroelectricity in bulk single-crystalline HfO2. Y. Nat. Mater. 20, 826–832 (2021).
Liu, S. & Hanrahan, B. M. Effects of growth orientations and epitaxial strains on phase stability of HfO2 thin films. Phys. Rev. Mater. 3, 054404 (2019).
Ding, W., Zhang, Y., Tao, L., Yang, Q. & Zhou, Y. The atomic-scale domain wall structure and motion in HfO2-based ferroelectrics: A first-principle study. Acta Mater 196, 556–564 (2020).
Anthony, S. M. & Granick, S. Image analysis with rapid and accurate two-dimensional gaussian fitting. Langmuir 25, 8152–8160 (2009).
Acknowledgements
This work is supported by National Natural Science Foundation of China (NO. 52571013 (W.R.G.), NO. 52201018 (W.R.G.), NO. 51971223 (Y.L.Z.), NO. 51901166 (S.R.Z.)), Guangdong Basic and Applied Basic Research Foundation (2024A1515140162 (W.R.G.), 2023A1515012796 (W.R.G.), 2021A1515110291 (W.R.G.)), Guangdong Provincial Quantum Science Strategic Initiative (GDZX2202001, GDZX2302001, GDZX2402001 (X.L.M.)), the Open Fund of the Microscopy Science and Technology, Songshan Lake Science City (202401202 (W.R.G.)). W.R.G. acknowledges the SLAB Young Scientists Program. We also acknowledge the XRD technical support provided by Y.Z. Chen at APEX TECHNOLOGIES.
Author information
Authors and Affiliations
Contributions
W.R.G. and B.R.W. contributed equally to this work. X.L.M. conceived the project on the architecture of quantum materials modulated by ferroelectric polarizations; W.R.G., Y.L.Z., and X.L.M. designed the sample structures and subsequent experiments. W.R.G. performed the thin-film growth and XRD observations. W.R.G. and B.R.W. performed the TEM and STEM observations. B.R.W. prepared the TEM samples. S.R.Z. and M.L. performed the digital analysis of the STEM data. All authors participated in the discussion and interpretation of the data.
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing interests.
Peer review
Peer review information
Nature Communications thanks Hyeon Han, Sean McMitchell and the other anonymous reviewer(s) for their contribution to the peer review of this work. A peer review file is available.
Additional information
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Supplementary information
Rights and permissions
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
About this article
Cite this article
Geng, WR., Wang, BR., Zhu, YL. et al. Roadmap of phase transitions in hafnia-based superlattice films. Nat Commun (2026). https://doi.org/10.1038/s41467-026-71265-7
Received:
Accepted:
Published:
DOI: https://doi.org/10.1038/s41467-026-71265-7
