ZnO基纤锌矿铁电体中矫顽场的起源与降低
Origin and Reduction of Coercive Fields in ZnO-based Wurtzite Ferroelectrics
- Bredesen Center for Interdisciplinary Research, University of Tennessee（田纳西大学布雷德森跨学科研究中心）
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory（橡树岭国家实验室纳米材料科学中心）
- Department of Mechanical Engineering, The Pennsylvania State University（宾夕法尼亚州立大学机械工程系）
- Department of Materials Science and Engineering, The Pennsylvania State University（宾夕法尼亚州立大学材料科学与工程系）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究通过反应分子动力学揭示ZnO基纤锌矿铁电体矫顽场由反演畴界丝状头部未屏蔽局域极化序控制，电荷掺杂比应变更有效，组合可降E_c约50%，并借层状结构缩短传播路径。
AI中文摘要：
纤锌矿铁电体为实现半导体兼容的非易失性器件提供了一条途径，但其较大的矫顽场（E$_c$）限制了极化反转、漏电和介电击穿之间的工作窗口。最近在纤锌矿氮化物中识别出了原子级局域且非经典的开关前沿，然而决定矫顽场的微观特征仍未解决。在此，我们使用以第一性原理数据参数化的大规模反应分子动力学，跟踪本征、Mg修饰和异质结构ZnO中场驱动的反转过程。反转通过崎岖的反演畴界丝状结构进行，这与最近在其他纤锌矿铁电体中的观察结果一致。我们发现，开关所需场由前进的丝状头部控制，该头部在瞬态开关动力学期间是一个欠配位的重构反演畴界区域，具有大的沿场方向的局域极化序振幅，该振幅仅被相反取向的周围壳层部分补偿。仅应变和仅电荷掺杂的受控扰动表明，电荷再分布比应变更有效地降低矫顽场，因为它抑制了丝状头部处这一决定场的未屏蔽局域极化序，其组合效应使E$_c$降低约50%。层状ZnO/ZnMgO结构进一步产生埋藏成核位点并缩短丝状传播长度。这些结果将原子级开关拓扑与大幅降低ZnO基纤锌矿铁电体中矫顽场的材料设计原则联系起来。
英文摘要：
Wurtzite ferroelectrics offer a route to semiconductor-compatible non-volatile devices, but their large coercive fields (E$_c$) constrain the operating window between polarization reversal, leakage and dielectric breakdown. Atomically localized and non-classical switching fronts have recently been identified in wurtzite nitrides, yet the microscopic feature that sets the coercive field remains unresolved. Here we use large-scale reactive molecular dynamics, parameterized against first-principles data, to follow field-driven reversal in pristine, Mg-modified and heterostructured ZnO. Reversal proceeds through rugged inversion-boundary filaments in agreement with recent observations in other wurtzite ferroelectrics. We find that the field required for switching is controlled by the advancing filament head, which is a under-coordinated reconstructed inversion-boundary region during the transient switching dynamics with a large field-aligned local polar-order amplitude that is only partially compensated by an oppositely oriented surrounding shell. Controlled strain-only and charge-doping-only perturbations show that charge redistribution lowers the coercive field more effectively than strain because it suppresses this field-setting unscreened local polar order at the filament head, with the combined effect lowering E$_c$ by $\sim$ 50 \%. Layered ZnO/ZnMgO architectures further create buried nucleation sites and shorten filament propagation lengths. These results connect atomistic switching topology to a materials-design principle for substantially reducing coercive fields in ZnO-based wurtzite ferroelectrics.
