Crystalline oxidic non-equilibrium phases: Preparation, nucleation, growth and stability

这个联合项目结合了三个研究小组和两个进一步的合作伙伴，在物理化学、固体物理和理论方面具有互补的实验方法和技能。将研究离子固溶体和大多数非化学计量固溶体中的相形成(从形核开始)和相生长。该项目的目的是回答关于衬底和基质对相形成和随后的生长步骤的影响以及对这些过程的控制的基本问题：a)固相基质对成核和相生长的影响是什么？b)在达到平衡状态的过程中，哪种反应路径采用固体和潜在的高度非化学计量比的非平衡体系，晶态非平衡相是中间形成的吗？c)能否用电化学方法来改变成核和反应路径？d)高浓度的掺杂对相形成和相稳定有什么影响？这三组的制备方法是互补的(溅射，PLD、电化学、高温化学、等离子体化学)，每个小组为联合项目提供不同的表征技术。高分辨电子显微镜和理论计算由两个合作伙伴提供。这些实验的重点并不是薄膜。我们研究厚度至少为1μm的样品，即块状材料。这三个小组在固态反应、无序固体和物理/物理化学表征技术建模方面的丰富经验也将被提供给该计划的其他项目。

This joint project combines three research groups and two further cooperation partners with complementary experimental methods and skills from Physical Chemistry, Solid State Physics and Theory. The phase formation (starting with nucleation) and phase growth in ionic and mostly non-stoichiometric solid solutions will be investigated. The aim of the project is to answer fundamental questions on the influence of substrate and matrix on phase formation and the subsequent growth steps, as also the control of these processes:a) What is the influence of the solid state matrix on nucleation and phase growth?b) Which reaction path takes a solid and potentially highly non-stoichiometric non-equilibrium system on the way to its equilibrium state, and are crystalline non-equilibrium phases intermediately formed?c) Can electrochemical methods be used to modify nucleation and reaction paths?d) What influence do dopants in high concentrations have on the phase formation and phase stability?The preparation methods of the three groups are complementary (Sputtering, PLD, electrochemistry, high temperature chemistry, plasma chemistry), and each group provides different characterization techniques to the joint project. High-resolution electron microscopy and theoretical calculations are provided by two cooperation partners. The experiments do not focus on thin films. We study samples with thicknesses in the order of at least 1 μm, i.e. bulk materials.The extensive experience of the three groups in modeling of solid state reactions, of disordered solids and physical/physico-chemical characterization techniques will also be offered to other projects in the program.