力电场作用下PZT/STO/PZT薄膜中铁电泡畴的拓扑演变机制研究

铁电畴是铁电材料最基本的微观结构，有望增加传感、驱动和信息存储器件的功能单元密度、提高其操作速度并降低能耗，在电子科技领域引起广泛关注。铁电畴中的泡畴具备在三维空间小于10nm的尺寸优势，但多场作用下畴变的动态特性及界面调控机理尚不明确。本项目以具有超薄介电夹层的PZT/STO/PZT膜为研究对象，拟采用原子分辨透射电子显微学方法，从平面和截面两个正交视角，全方位观测该铁电多层膜内泡畴的结构特性；同时利用原位实验，探究在力、电场及二者协同效应下泡畴实时的拓扑转变规律；最后在界面处进行亚埃级空间分辨率的应力状态、原子位移以及元素价态精细表征，以此研究多层膜体系中最为关键的层间相互作用。本研究将揭示多外场协同效应与铁电泡畴内部力电耦合的实时交互作用，阐明多层铁电薄膜中介电/铁电界面对畴变的调控机制，最终实现可控的铁电拓扑结构转变，为复合功能微纳电子器件的结构设计和性能优化提供科学依据。

Ferroelectric domains, the most basic microstructures in ferroelectric materials, have drawn great interest in the field of electronic devices due to their potential to increase the density of functional units, boost the speed of operation, reduce energy consumption in sensor, actuator and memory devices. Among them, ferroelectric bubbles have advantages in size (~10 nm in three dimensions) but the domain switching dynamics and interfacial interaction under multi-field coupling still remain elusive. The proposal focuses on series of PZT/STO/PZT films where ultra-thin dielectric spacers are sandwiched. In-situ experiment and transmission electron microscopy with atomic resolution will be combined during the investigation of bubble domain switching under stress and/or electric field. Both plan view and cross-sectional view are scheduled for 3D visualization of the bubble domain topological transition. Strain field, atomic displacement and valence states of the elements will also be analyzed to study the most critical interfacial interaction in the multilayer system. The study is proposed to reveal the interplay between synergistic effects of stress/electric field and lattice-polarization coupling in bubble domains. Moreover, the results can elucidate interfacial interaction between dielectric and ferroelectric layers that manipulate the domain switching. Thus, they shed light on more deterministic topological transition and provide new pathways for the design and performance optimization of multifunctional micronanoelectronic devices.