AI 中文总结
该研究发现Zn₁₋ₓMgₓO的极化反转无横向畴壁迁移率，通过垂直柱状丝形核实现，与钙钛矿的生长介导开关机制不同，明确了其形核主导的开关特性。
AI 中文摘要
铁电体的极化反转源于畴形核与后续生长的耦合过程，但经典钙钛矿氧化物与新型纤锌矿铁电体的主导机制存在根本差异。钙钛矿的开关通常由可移动畴壁主导，其场驱动传播决定宏观动力学；而本研究显示，纤锌矿Zn₁₋ₓMgₓO的极化反转遵循完全不同的路径。结合扫描振荡器显微镜与点脉冲成像方法，直接绘制局部开关事件与畴壁响应，发现Zn₁₋ₓMgₓO中的畴壁表现出可忽略的横向迁移率（小于10nm），极化反转主要通过垂直延伸的柱状丝形核实现，其横向尺寸与晶粒相当。这种形核控制的开关与钙钛矿铁电体典型的生长介导动力学形成鲜明对比，解释了纤锌矿体系中观察到的突发、空间局域化开关行为。这些结果确立了形核主导的丝状反转是Zn₁₋ₓMgₓO的决定性开关机制，并指出需进一步研究不同晶粒尺寸下的关联长度与形核过程。
英文摘要
Polarization reversal in ferroelectrics arises from the coupled processes of domain nucleation and subsequent growth, yet the governing mechanisms differ fundamentally between classical perovskite oxides and emerging wurtzite ferroelectrics. While switching in perovskites is typically governed by mobile domain walls whose field-driven propagation dominates macroscopic kinetics, here we show that polarization reversal in wurtzite Zn1-xMgxO proceeds through a qualitatively different pathway. Using scanning oscillator microscopy, in combination with point pulse-imaging methods, we directly map local switching events and domain wall responses, revealing that domain walls in Zn1-xMgxO exhibit negligible lateral mobility (sub 10nm) and that polarization reversal proceeds predominantly through the nucleation of vertically extended columnar filaments with a lateral size on the order of the grains. This nucleation-controlled switching contrasts sharply with the growth-mediated dynamics characteristic of perovskite ferroelectrics and explains the abrupt, spatially localized switching behavior observed in wurtzite systems. These results establish nucleation-dominated filamentary reversal as a defining switching mechanism in Zn1-xMgxO and point towards the need for further studies to understand correlation lengths and nucleation processes across a range of grain sizes.
Comments14 pages, 5 figures
