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| Main Authors: | , , , , , , |
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| Format: | Preprint |
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2024
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2403.09426 |
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| _version_ | 1866909603186343936 |
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| author | Yang, Jiyuan Wu, Jing Li, Jingxuan Zhou, Chao Sun, Yang Chen, Zuhuang Liu, Shi |
| author_facet | Yang, Jiyuan Wu, Jing Li, Jingxuan Zhou, Chao Sun, Yang Chen, Zuhuang Liu, Shi |
| contents | The high coercive field ($E_c$) of hafnia-based ferroelectrics presents a major obstacle to their applications. The ferroelectric switching mechanisms in hafnia that dictate $E_c$, especially those related to domain nucleation in the Nucleation-Limited-Switching (NLS) model and domain wall motion in the Kolmogorov-Avrami-Ishibas (KAI) model, have remained elusive. We develop a deep-learning-assisted multiscale approach, incorporating atomistic insights into the critical nucleus, to predict both NLS- and KAI-type coercive fields. The theoretical NLS-type $E_c$ values agree with previous experimental results as well as our own measurements and also exhibit the correct thickness scaling for films between 3 and 20 nm. Combined theoretical and experimental investigations reveal that the giant $E_c$ in hafnia-based ferroelectrics arises from the ultra-thin geometry, which confines switching to the NLS mechanism. We predict that the theoretical lower limit for KAI-type $E_c$ is 0.1 MV/cm arsing from mobile domain walls. The activation of KAI-type switching to achieve lower $E_c$ is supported by our experimental demonstration of a low coercive field of 1 MV/cm in a 60 nm ferroelectric (HfO$_2$)$_n$/(ZrO$_2$)$_n$ ($n=3$ unit cells) superlattices. These findings establish a comprehensive framework for understanding ferroelectric switching in hafnia and highlight the potential of geometry and domain-wall engineering to achieve low-$E_c$ devices. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2403_09426 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Theoretical lower limit of coercive field in ferroelectric hafnia Yang, Jiyuan Wu, Jing Li, Jingxuan Zhou, Chao Sun, Yang Chen, Zuhuang Liu, Shi Materials Science The high coercive field ($E_c$) of hafnia-based ferroelectrics presents a major obstacle to their applications. The ferroelectric switching mechanisms in hafnia that dictate $E_c$, especially those related to domain nucleation in the Nucleation-Limited-Switching (NLS) model and domain wall motion in the Kolmogorov-Avrami-Ishibas (KAI) model, have remained elusive. We develop a deep-learning-assisted multiscale approach, incorporating atomistic insights into the critical nucleus, to predict both NLS- and KAI-type coercive fields. The theoretical NLS-type $E_c$ values agree with previous experimental results as well as our own measurements and also exhibit the correct thickness scaling for films between 3 and 20 nm. Combined theoretical and experimental investigations reveal that the giant $E_c$ in hafnia-based ferroelectrics arises from the ultra-thin geometry, which confines switching to the NLS mechanism. We predict that the theoretical lower limit for KAI-type $E_c$ is 0.1 MV/cm arsing from mobile domain walls. The activation of KAI-type switching to achieve lower $E_c$ is supported by our experimental demonstration of a low coercive field of 1 MV/cm in a 60 nm ferroelectric (HfO$_2$)$_n$/(ZrO$_2$)$_n$ ($n=3$ unit cells) superlattices. These findings establish a comprehensive framework for understanding ferroelectric switching in hafnia and highlight the potential of geometry and domain-wall engineering to achieve low-$E_c$ devices. |
| title | Theoretical lower limit of coercive field in ferroelectric hafnia |
| topic | Materials Science |
| url | https://arxiv.org/abs/2403.09426 |