School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, New South Wales2006, Australia.
Key Laboratory for Quantum Materials of Zhejiang Province, Department of Physics, School of Science, Westlake University, Hangzhou, Zhejiang310030, China.
ACS Appl Mater Interfaces. 2023 Jan 11;15(1):2313-2318. doi: 10.1021/acsami.2c14598. Epub 2022 Dec 19.
Domain walls (DWs) in ferroelectric materials are interfaces that separate domains with different polarizations. Charged domain walls (CDWs) and neutral domain walls are commonly classified depending on the charge state at the DWs. CDWs are particularly attractive as they are configurable elements, which can enhance field susceptibility and enable functionalities such as conductance control. However, it is difficult to achieve CDWs in practice. Here, we demonstrate that applying mechanical stress is a robust and reproducible approach to generate CDWs. By mechanical compression, CDWs with a head/tail-to-body configuration were introduced in ultrathin BaTiO, which was revealed by in-situ transmission electron microscopy. Finite element analysis shows strong strain fluctuation in ultrathin BaTiO under compressive mechanical stress. Molecular dynamics simulations suggest that the strain fluctuation is a critical factor in forming CDWs. This study provides insight into ferroelectric DWs and opens a pathway to creating CDWs in ferroelectric materials.
铁电材料中的畴壁（DWs）是分离具有不同极化的畴的界面。根据 DW 处的电荷状态，通常将带电畴壁（CDWs）和中性畴壁进行分类。CDWs 特别有吸引力，因为它们是可配置的元件，可以增强场灵敏度并实现诸如电导控制等功能。然而，在实践中很难实现 CDWs。在这里，我们证明施加机械应力是一种生成 CDWs 的稳健且可重复的方法。通过机械压缩，在原位透射电子显微镜下揭示了具有头/尾-体构型的 CDWs 被引入超薄 BaTiO3 中。有限元分析表明，在压缩机械应力下，超薄 BaTiO3 中存在强烈的应变波动。分子动力学模拟表明，应变波动是形成 CDWs 的关键因素。这项研究深入了解了铁电 DWs，并为在铁电材料中创建 CDWs 开辟了途径。
