AI 中文总结
研究铁电体HZO中脉冲驱动累积极化切换，采用相场模型，通过改变多种参数建立微观与宏观联系，揭示有效切换畴半径的不同标度区域及转变机制，为相关器件提供设计指南。
AI 中文摘要
由连续亚 coercive 电场脉冲驱动的累积极化切换为低功耗铁电存储器和神经形态器件提供了一条有前景的途径。然而，控制这种非平衡过程的动力学机制仍知之甚少。在此，我们采用基于含时朗道-金兹堡形式的相场模型来研究铁电体 HZO 中的脉冲驱动累积切换。通过系统改变初始畴构型、脉冲幅度、脉冲开启时间和脉冲关闭时间，我们建立了微观畴壁动力学与宏观极化累积之间的定量联系。我们表明有效切换畴半径遵循由局部动力学指数表征的不同标度区域。最初，大于1的局部指数表明在连续脉冲下由增强的不可逆畴壁传播驱动的超线性畴生长。随着切换进展，接近1的局部指数标志着稳定的自相似生长，而小于1的局部指数表示由几何限制、可切换极化耗尽和弛豫诱导的反向切换引起的动力学减速。这些区域之间的转变由脉冲开启间隔期间的场驱动激发与脉冲关闭间隔期间的自发弛豫之间的竞争控制。初始畴几何形状进一步影响这种转变。增加脉冲幅度或脉冲开启持续时间会扩展超线性区域，而更长的脉冲关闭时间会促进弛豫并抑制累积。这些发现为脉冲驱动累积切换建立了一个统一的标度框架，为非平衡铁电畴演化提供了定量见解，并为基于HZO的存储器和神经形态器件提供了设计指南。
英文摘要
Accumulative polarization switching driven by sequential sub-coercive electric-field pulses offers a promising route toward low-power ferroelectric memories and neuromorphic devices. However, the kinetic regimes governing this nonequilibrium process remain poorly understood. Here, we employ a phase-field model based on the time-dependent Landau-Ginzburg formalism to investigate pulse-driven accumulative switching in ferroelectric HZO. By systematically varying the initial domain configuration, pulse amplitude, pulse-on time, and pulse-off time, we establish a quantitative link between microscopic domain-wall dynamics and macroscopic polarization accumulation. We show that the effective switched-domain radius follows distinct scaling regimes characterized by the local kinetic exponent. Initially, a local exponent greater than 1 indicates superlinear domain growth driven by enhanced irreversible domain-wall propagation under successive pulses. As switching progresses, a local exponent close to unity marks steady self-similar growth, whereas a local exponent less than 1 signifies decelerating dynamics caused by geometric confinement, depletion of switchable polarization, and relaxation-induced back switching. The transition between these regimes is governed by the competition between field-driven excitation during the pulse-on interval and spontaneous relaxation during the pulse-off interval. The initial domain geometry further influences this transition. Increasing the pulse amplitude or pulse-on duration extends the superlinear regime, whereas longer pulse-off times promote relaxation and suppress accumulation. These findings establish a unified scaling framework for pulse-driven accumulative switching, providing quantitative insight into nonequilibrium ferroelectric domain evolution and design guidelines for HZO-based memory and neuromorphic devices.
Comments21 pages, 12 figures
