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| Main Authors: | , , , , , , , , , , |
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| Format: | Preprint |
| Published: |
2024
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2409.12434 |
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| _version_ | 1866912034696724480 |
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| author | Gao1, Xiaoyue Liu, Zhuohui Han, Bo Zhang, Xiaowen Mao, Ruilin Shi, Ruochen Zhu, Ruixue Lu, Jiangbo Wang, Tao Ge, Chen Gao, Peng |
| author_facet | Gao1, Xiaoyue Liu, Zhuohui Han, Bo Zhang, Xiaowen Mao, Ruilin Shi, Ruochen Zhu, Ruixue Lu, Jiangbo Wang, Tao Ge, Chen Gao, Peng |
| contents | Hf0.5Zr0.5O2 (HZO) is a promising candidate for next generation ferroelectric memories and transistors. However, its ferroelectricity origin is still under debate due to the complex of its phase and microstructure in practical samples. In this study, we investigate the atomic structure of substrate-free HZO freestanding film with multislice electron ptychography, for which the ultra-high space resolution (up to ~25 pm) and capability to simultaneously image the cation and oxygen allow us to precisely determine the intrinsic atomic structures of different phases and reveal subtle changes among them. We clarify that the orthorhombic phase is ferroelectric with spontaneous polarization ~34{\pm}4 μC/cm2 (corresponding to 56{\pm}6 pm in displacement) that is accurately measured through statistical analysis. Significant polarization suppression is observed near the grain boundary, while no distinguishable structural changes are detected near the 180° ferroelectric domain walls. Through the direct oxygen imaging of orthorhombic phase from the [111] zone axis, we quantify a substantial number of oxygen vacancies with a preferential distribution, which influences the polarization direction and strength. These findings provide fundamentals for HZO research, and thus lay a foundation for the design of high-performance ferroelectric devices. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2409_12434 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Precise structure and polarization determination of Hf0.5Zr0.5O2 with electron ptychography Gao1, Xiaoyue Liu, Zhuohui Han, Bo Zhang, Xiaowen Mao, Ruilin Shi, Ruochen Zhu, Ruixue Lu, Jiangbo Wang, Tao Ge, Chen Gao, Peng Materials Science Mesoscale and Nanoscale Physics Hf0.5Zr0.5O2 (HZO) is a promising candidate for next generation ferroelectric memories and transistors. However, its ferroelectricity origin is still under debate due to the complex of its phase and microstructure in practical samples. In this study, we investigate the atomic structure of substrate-free HZO freestanding film with multislice electron ptychography, for which the ultra-high space resolution (up to ~25 pm) and capability to simultaneously image the cation and oxygen allow us to precisely determine the intrinsic atomic structures of different phases and reveal subtle changes among them. We clarify that the orthorhombic phase is ferroelectric with spontaneous polarization ~34{\pm}4 μC/cm2 (corresponding to 56{\pm}6 pm in displacement) that is accurately measured through statistical analysis. Significant polarization suppression is observed near the grain boundary, while no distinguishable structural changes are detected near the 180° ferroelectric domain walls. Through the direct oxygen imaging of orthorhombic phase from the [111] zone axis, we quantify a substantial number of oxygen vacancies with a preferential distribution, which influences the polarization direction and strength. These findings provide fundamentals for HZO research, and thus lay a foundation for the design of high-performance ferroelectric devices. |
| title | Precise structure and polarization determination of Hf0.5Zr0.5O2 with electron ptychography |
| topic | Materials Science Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2409.12434 |