Abstract
Hafnia-based ferroelectric materials have garnered considerable attention due to robust ferroelectricity in ultrathin films and excellent compatibility with silicon-based technology. Theoretical predictions of the polarization along [001] direction of ferroelectric HfO2 are 50 μC/cm2 and 70 μC/cm2, respectively, depending on the switching mechanism. However, most experimental observations of the intrinsic polarization are much lower than these predictions. Here, we report that an intrinsic remnant polarization up to 40 μC/cm2 is achieved in epitaxially grown (111)-oriented Hf0.5Zr0.5O2/Hf0.9La0.1O2 multilayer film, corresponding to 69.3 μC/cm2 along [001], approaching the theoretical limit. Structural analyses reveal a rhombohedral-distorted orthorhombic phase in the Hf0.5Zr0.5O2/Hf0.9La0.1O2 multilayers, stabilized by an in-plane compressive strain. Density functional theory calculations demonstrate that La doping in Hf0.5Zr0.5O2/Hf0.9La0.1O2 promotes an unconventional switching pathway and contributes to the high intrinsic polarization. These findings provide a compelling strategy for achieving high intrinsic polarization and establish a design paradigm for high-performance hafnia-based ferroelectric devices.
Data availability
The data generated and analyzed during the current study are available from the corresponding authors on reasonable request.
References
Cheema, S. S. et al. Ultrathin ferroic HfO2–ZrO2 superlattice gate stack for advanced transistors. Nature 604, 65–71 (2022).
Luo, Q. et al. A highly CMOS compatible hafnia-based ferroelectric diode. Nat. Commun. 11, 1391 (2020).
Cheema, S. S. et al. Emergent ferroelectricity in subnanometer binary oxide films on silicon. Science 376, 648–652 (2022).
Cheema, S. S. et al. Enhanced ferroelectricity in ultrathin films grown directly on silicon. Nature 580, 478–482 (2020).
Nukala, P. et al. Reversible oxygen migration and phase transitions in hafnia-based ferroelectric devices. Science 372, 630–635 (2021).
Lee, H.-J. et al. Scale-free ferroelectricity induced by flat phonon bands in HfO2. Science 369, 1343–1347 (2020).
Chernikova, A. et al. Ultrathin Hf0.5Zr0.5O2 Ferroelectric Films on Si. ACS Appl. Mater. Interfaces 8, 7232–7237 (2016).
Tian, X. et al. Evolution of ferroelectric HfO2 in ultrathin region down to 3 nm. Appl. Phys. Lett. 112, 102902 (2018).
Zhu, T., Ma, L., Deng, S. & Liu, S. Progress in computational understanding of ferroelectric mechanisms in HfO2. Npj Comput. Mater. 10, 1–18 (2024).
Cao, J., Shi, S., Zhu, Y. & Chen, J. An overview of ferroelectric hafnia and epitaxial growth. Phys. Status Solidi Rapid Res. Lett 15, 2100025 (2021).
Kang, S. et al. Highly enhanced ferroelectricity in HfO2-based ferroelectric thin film by light ion bombardment. Science 376, 731–738 (2022).
Kim, H. et al. A simple strategy to realize super stable ferroelectric capacitor via interface engineering. Adv. Mater. Interfaces 9, 2102528 (2022).
Tai, L. et al. Significant reliability improvement by inducing dual atomic-thin titanium intercalation layers in Hf0.5Zr0.5O2 Films. IEEE Electron Device Lett. 44, 753–756 (2023).
Park, M. H. et al. A comprehensive study on the structural evolution of HfO2 thin films doped with various dopants. J. Mater. Chem. C 5, 4677–4690 (2017).
Chouprik, A., Negrov, D., Tsymbal, E. Y. & Zenkevich, A. Defects in ferroelectric HfO2. Nanoscale 13, 11635–11678 (2021).
Batra, R., Huan, T. D., Rossetti, G. A. & Ramprasad, R. Dopants promoting ferroelectricity in hafnia: insights from a comprehensive chemical space exploration. Chem. Mater. 29, 9102–9109 (2017).
Böscke, T. S., Müller, J., Bräuhaus, D., Schröder, U. & Böttger, U. Ferroelectricity in hafnium oxide thin films. Appl. Phys. Lett. 99, 102903 (2011).
Müller, J. et al. Ferroelectric hafnium oxide: A CMOS-compatible and highly scalable approach to future ferroelectric memories. In 2013 IEEE International Electron Devices Meeting 10.8.1-10.8.4 (2013).
Park, M. H. et al. Ferroelectricity and Antiferroelectricity of Doped Thin HfO2-Based Films. Adv. Mater. 27, 1811–1831 (2015).
Zhou, C. et al. Enhanced polarization switching characteristics of HfO2 ultrathin films via acceptor-donor co-doping. Nat. Commun. 15, 2893 (2024).
Lee, Y. H. et al. Preparation and characterization of ferroelectric Hf0.5Zr0.5O2 thin films grown by reactive sputtering. Nanotechnology 28, 305703 (2017).
Mueller, S. et al. Incipient ferroelectricity in Al-doped HfO2 thin films. Adv. Funct. Mater. 22, 2412–2417 (2012).
Mimura, T., Shimizu, T., Uchida, H., Sakata, O. & Funakubo, H. Thickness-dependent crystal structure and electric properties of epitaxial ferroelectric Y2O3-HfO2 films. Appl. Phys. Lett. 113, 102901 (2018).
Yun, Y. et al. Intrinsic ferroelectricity in Y-doped HfO2 thin films. Nat. Mater. 21, 974–980 (2022).
Guo, J. et al. Rhombohedral R3 phase of Mn-doped Hf0.5Zr0.5O2 epitaxial films with robust ferroelectricity. Adv. Mater. 36, 2406038 (2024).
Wei, Y. et al. A rhombohedral ferroelectric phase in epitaxially strained Hf0.5Zr0.5O2 thin films. Nat. Mater. 17, 1095–1100 (2018).
Shi, S. et al. Interface-engineered ferroelectricity of epitaxial Hf0.5Zr0.5O2 thin films. Nat. Commun. 14, 1780 (2023).
Shi, S. et al. Stabilizing the ferroelectric phase of Hf0.5Zr0.5O2 thin films by charge transfer. Phys. Rev. Lett. 133, 036202 (2024).
Estandía, S. et al. Engineering ferroelectric Hf0.5Zr0.5O2 thin films by epitaxial stress. ACS Appl. Electron. Mater. 1, 1449–1457 (2019).
Song, T. et al. Disentangling stress and strain effects in ferroelectric HfO2. Appl. Phys. Rev. 10, 041415 (2023).
Shiraishi, T. et al. Impact of mechanical stress on ferroelectricity in (Hf0.5Zr0.5)O2 thin films. Appl. Phys. Lett. 108, 262904 (2016).
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).
Wu, Y. et al. Unconventional polarization-switching mechanism in (Hf,Zr)O2 ferroelectrics and its implications. Phys. Rev. Lett. 131, 226802 (2023).
Yang, P., Liu, H., Chen, Z., Chen, L. & Wang, J. Unit-cell determination of epitaxial thin films based on reciprocal-space vectors by high-resolution X-ray diffractometry. J. Appl. Crystallogr. 47, 402–413 (2014).
Adkins, J. W., Fina, I., Sánchez, F., Bakaul, S. R. & Abiade, J. T. Thermal evolution of ferroelectric behavior in epitaxial Hf0.5Zr0.5O2. Appl. Phys. Lett. 117, 142902 (2020).
Lee, J. S., Lee, S. & Noh, T. W. Resistive switching phenomena: A review of statistical physics approaches. Appl. Phys. Rev. 2, 031303 (2015).
Hytch, M. J., Snoeck, E. & Kilaas, R. Quantitative measurement of displacement and strain fields from HREM micrographs. Ultramicroscopy 74, 133–146 (1998).
Li, T. et al. Origin of ferroelectricity in epitaxial Si-doped HfO2 films. ACS Appl. Mater. Interfaces 11, 4139–4144 (2019).
Yoong, H. Y. et al. Epitaxial ferroelectric Hf0.5Zr0.5O2 thin films and their implementations in memristors for brain-inspired computing. Adv. Funct. Mater. 28, 1806037 (2018).
Lyu, J. et al. Enhanced ferroelectricity in epitaxial Hf0.5Zr0.5O2 thin films integrated with Si(001) using SrTiO3 templates. Appl. Phys. Lett. 114, 222901 (2019).
Wang, Y. et al. A stable rhombohedral phase in ferroelectric Hf(Zr)1+xO2 capacitor with ultralow coercive field. Science 381, 558–563 (2023).
Shimizu, T. et al. The demonstration of significant ferroelectricity in epitaxial Y-doped HfO2 film. Sci. Rep. 6, 32931 (2016).
Katayama, K. et al. Growth of (111)-oriented epitaxial and textured ferroelectric Y-doped HfO2 films for downscaled devices. Appl. Phys. Lett. 109, 112901 (2016).
Song, T. et al. Epitaxial ferroelectric La-doped Hf0.5Zr0.5O2 thin films. ACS Appl. Electron. Mater. 2, 3221–3232 (2020).
Lyu, J., Fina, I., Solanas, R., Fontcuberta, J. & Sánchez, F. Growth window of ferroelectric epitaxial Hf0.5Zr0.5O2 thin films. ACS Appl. Electron. Mater. 1, 220–228 (2019).
Lyu, J., Song, T., Fina, I. & Sánchez, F. High polarization, endurance and retention in sub-5 nm Hf0.5Zr0.5O2 films. Nanoscale 12, 11280–11287 (2020).
Acknowledgements
This work was carried out with the support of BL02U2 at Shanghai Synchrotron Radiation Facility. Funding: Singapore National Research Foundation Investigatorship (Grant No. NRF-NRFI08-2022-0009). MOE-T2EP50121-0011, MOE-T2EP50223-0006, Science and Technology Project of Jiangsu Province (BZ2022056), National Natural Science Foundation Joint Regional Innovation Development Project (Grant No. U23A20365), National key R & D plan “nano frontier” key special project (Grant No. 2021YFA1200502), Cultivation projects of national major R & D project (Grant No. 92164109), National Natural Science Foundation of China (Grant No. 61874158, No. 62004056, and No. 62104058), National Natural Science Foundation of China (12125407, 12404115), Zhejiang Provincial Natural Science Foundation (LD21E020003), Joint Funds of the National Natural Science Foundation of China (U21A2067), National Key Research and Development Program of China (No.2021YFA1500800), National Science Foundation through the EPSCoR RII Track-1 program (NSF Grant No. OIA-2044049). National Natural Science Foundation of China (Program No. 12474061), Natural Science Basic Research Program of Shaanxi (Program No. 2024JC-YBMS-009), The Youth Project of “Shanxi High-level Talents Introduction Plan (5113240032)”.
Author information
Authors and Affiliations
Contributions
S.S. and J.C. came up with the original idea; S.S. performed thin film deposition, ferroelectric tests and structural characterizations of the films; T.C. and E.Y.T. developed the theoretical concept; F.S. and Z.Z. contributed to the theoretical calculations; H.X., Z.L., and H.T. performed the STEM experiments; H.S. contributed to thin film deposition and ferroelectric tests; Y.S. and X.G. contributed to ferroelectric measurements at cryogenic temperatures; G.H., J.N., P.Y., and W.C. contributed to the data analysis; X.Y., H.T., T.C., and J.C. supervised this work; S.S., T.C., and J.C. wrote the manuscript, and all authors contributed to its final version.
Corresponding authors
Ethics declarations
Competing interests
The authors declare no competing interests.
Peer review
Peer review information
Nature Communications thanks Jamal Belhadi 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-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, 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 you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. 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-nc-nd/4.0/.
About this article
Cite this article
Shi, S., Xi, H., Su, H. et al. Approaching theoretical polarization limit in HfZrO2/HfLaO2 multilayers. Nat Commun (2026). https://doi.org/10.1038/s41467-026-69634-3
Received:
Accepted:
Published:
DOI: https://doi.org/10.1038/s41467-026-69634-3
