发表机构
University of Tennessee（田纳西大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出统一热力学框架，分析离子补偿铁电薄膜中极化与表面电荷耦合及畴形成，揭示微分化学电容作用，并给出BaTiO3中化学屏蔽稳定均匀态或畴形成的实验可测条件。
AI 中文摘要
与离子或分子储层接触的铁电表面本质上是一种铁离子态，其中极化与补偿表面电荷在热力学上耦合。已知表面化学补偿可控制铁电极化的大小和符号，但对畴形成的竞争性不稳定性通常被单独处理。在此，我们发展了一种静态理论，在单轴极化取向的统一热力学框架内分析极化、电化学表面电荷和有限波矢畴形成。核心量是微分化学电容，它决定了表面电荷对极化空间调制的响应强度，因此与平衡屏蔽电荷有根本区别。我们推导了均匀状态方程、有限波矢稳定性核、解析的畴起始波长和厚度标度，以及针对二级和一级铁电体的弱非线性条纹和棋盘格解。对于一级相变，当有效四次系数为负时，有限振幅条纹态可在均匀线性旋节线之前变得热力学有利；随着偏置背景极化增加，该旋节线前窗口关闭。密集的数值相图证实了解析结构，并展示了化学势和薄膜厚度如何重组弱极化、单畴和多畴态。针对BaTiO3实现的数值分析说明了相应的温度、氧压和厚度标度，并识别了可实验测试的区间，在这些区间内化学屏蔽稳定均匀态以抵抗此处考虑的柱状180°不稳定性，或者畴形成成为降低退极化能的优选途径。
英文摘要
A ferroelectric surface in contact with an ionic or molecular reservoir is intrinsically a ferroionic state in which polarization and compensating surface charge are thermodynamically coupled. Surface chemical compensation is known to control the magnitude and sign of ferroelectric polarization, yet the competing instability toward domain formation has usually been treated separately. Here we develop a static theory in which polarization, electrochemical surface charge, and finite-wave-vector domain formation are analyzed within a single thermodynamic framework for uniaxial polarization orientation. The central quantity is the differential chemical capacitance, which determines how strongly the surface charge can respond to a spatial modulation of polarization and therefore differs fundamentally from the equilibrium screening charge. We derive the homogeneous equation of state, the finite-wave-vector stability kernel, analytical domain-onset wavelengths and thickness scalings, and weakly nonlinear stripe and checkerboard solutions for both second- and first-order ferroelectrics. For a first-order transition, a finite-amplitude stripe state can become thermodynamically favorable before the homogeneous linear spinodal when the effective quartic coefficient is negative; this pre-spinodal window closes as the biased background polarization increases. Dense numerical phase maps confirm the analytical structure and show how chemical potential and film thickness reorganize weakly polar, monodomain, and polydomain states. Numerical analysis for BaTiO3 realization illustrates the corresponding temperature, oxygen-pressure, and thickness scales and identifies experimentally testable regimes in which chemical screening stabilizes the homogeneous state against the columnar 180° instability considered here or domain formation becomes the preferred route for depolarization-energy reduction.
