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

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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.