工程化晶界相称性以实现铪基薄膜中铁电稳定性
Engineering Grain Boundary Commensurability for Ferroelectric Stabilization in Hafnia-Based Films
- Rice University（莱斯大学）
- Rice Advanced Materials Institute, Rice University（莱斯大学先进材料研究所）
- University of Pennsylvania（宾夕法尼亚大学）
- Texas A&M University（德克萨斯农工大学）
- University of California, Berkeley（加州大学伯克利分校）
- Advanced Photon Source, Argonne National Laboratory（阿贡国家实验室先进光子源）
- Smalley-Curl Institute, Rice University（莱斯大学斯马利-柯尔研究所）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
通过实验和模拟证明晶界相称性稳定HZO薄膜极性正交相，外延工程化使剩余极化提升约60%，为设计铁电界面提供新自由度。
AI中文摘要：
晶界通过破坏长程对称性从根本上决定了多晶材料的宏观性质。在铁电体中，这些结构不连续通常被视为有害特征，它们会诱发退极化场并积累缺陷，从而抑制或钉扎局部极化。在此，我们证明晶界的相称性内在决定了多晶Hf0.5Zr0.5O2（HZO）薄膜中极性正交相的稳定性。利用深度分辨的多层电子叠层成像技术，我们以原子分辨率绘制了不同晶界上的三维（3D）相分布，揭示出高度相称的晶界通过补偿晶格失配并缓解几何阻挫，有效抑制了非极性四方相。蒙特卡洛模拟揭示了极性相稳定的原子和能量起源，表明相称晶界比其他晶界更强烈地有利于极性正交相。在此原理指导下，我们通过外延工程化HZO薄膜以促进相称晶界的优先形成，使铁电器件的剩余极化增强了约60%。这些发现提供了直接的三维实验和理论证据，确立了晶界相称性作为设计功能界面的关键自由度，指导新型陶瓷和多晶铁电体的构建。
英文摘要：
Grain boundaries fundamentally dictate the macroscopic properties of polycrystalline materials by breaking long-range symmetry. In ferroelectrics, these structural discontinuities are conventionally considered as detrimental features that induce depolarization fields and accumulate defects, thereby suppressing or pinning local polarization. Here, we demonstrate that the commensurability of grain boundaries inherently governs the polar-orthorhombic phase stability in polycrystalline Hf0.5Zr0.5O2 (HZO) thin films. Using depth-resolved multislice electron ptychography, we map the three-dimensional (3D) phase distribution across diverse boundaries with atomic resolution, revealing that highly commensurate grain boundaries effectively suppress the nonpolar-tetragonal phase by compensating for lattice mismatch while mitigating geometric frustration. Monte Carlo simulations uncover the atomistic and energetic origins of polar-phase stabilization, showing that commensurate grain boundaries favor the polar-orthorhombic phase more strongly than other grain boundaries. Guided by this principle, we epitaxially engineer HZO thin films to promote the preferential formation of commensurate grain boundaries, resulting in an approximately 60% enhancement in the remanent polarization of ferroelectric devices. These findings provide direct 3D experimental and theoretical evidence that establishes grain boundary commensurability as a critical degree of freedom for designing functional interfaces, guiding the construction of novel ceramics and polycrystalline ferroelectrics.
