Local atomic-scale structure of ionic conducting oxides from atom probe tomography

固态材料的原子排列、势能面和离子电导率是密切相关的。固体中原子的化学特性、电子结构和局部排列决定了势能分布，而势能分布又控制着移动的物质的能量学和动力学。它们的运动改变了原子结构，改变了能量格局，导致了一种耦合的动态状态。通过对溶解度、分凝系数、离子传导性和扩散的实验研究，可以深入了解能源前景。结合理论，这些研究提供了基础，发展一个完整的图片之间的动态耦合原子尺度结构和迁移率。ELSICS研究单位的目标是应用这种方法来获得在几个模型技术相关的离子导体的离子迁移率的机械理解。原子探针层析成像（APT）已经出现在过去几十年作为一个强大的方法来获得本地，原子尺度的三维元素分布的信息材料。即使是具有挑战性的材料，如电绝缘，离子导电和脆性氧化物已成功地分析使用激光激发和仔细优化的测量参数和重建算法。在拟议的研究单位范围内，APT将与西姆斯合并（P1 Weitzel），NMR（P2 Vogel）和TEM（P4 Jooss）来确定几种离子导体的浓度梯度和原子尺度结构，从理论上预测了位置能量分布和离子电导率（P5 Maass和P6 Jacob），并与CAIT（P1 Weitzel）和NMR（P2 Vogel）的离子运动测量进行了比较。最近，原子探针方法也被用来获得信息的个别离子动力学使用选择性场蒸发和随后的APT。这种方法的可能性和潜力，以检测在离子导体的局部迁移路径也将进行探讨。

Atomic arrangements, potential energy landscapes and ion conductivities of solid state materials are intimately interconnected. The chemical identity, electronic structure and local arrangement of atoms in a solid prescribes the potential energy landscape, and this in turn controls the energetics and kinetics of the mobile species. Their motion changes the atomic structure and shifts the energy landscape, leading to a coupled and dynamic state. Insights into the energy landscape can be gained from experimental studies of solubilities, segregation coefficients and ion conductivity and diffusion. Combined with theory, these studies provide the basis for developing a complete picture of the dynamic coupling between atomic scale structure and mobility. The goal of the ELSICS Research Unit is to apply this methodology to gain a mechanistic understanding of ion mobility in several model technologically relevant ion conductors.Atom probe tomography (APT) has emerged over the last several decades as a powerful method to obtain local, atomic-scale information of three-dimensional element distributions in materials. Even challenging materials such as electrically insulating, ionic conducting, and brittle oxides have been successfully analysed using laser excitation and by careful optimization of measurement parameters and reconstruction algorithms. In the context of the proposed Research Unit, APT will be combined with SIMS (P1 Weitzel), NMR (P2 Vogel), and TEM (P4 Jooss) to determine concentration gradients and atomic scale structure of several ion conductors, from which site energy distributions and ion conductivity will be predicted by theory (P5 Maass and P6 Jacob) and compared with measurements of ion motion with CAIT (P1 Weitzel) and NMR (P2 Vogel). Very recently, atom probe methods have also been used to gain information about individual ion dynamics using selective field evaporation and subsequent APT. The possibilities and potential of this method to detect local migration paths in ion conductors will also be explored.