SPP 1134: Transient structures in condensed matter investigated by ultrafast x-ray techniques

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The priority programme is devoted to ultrafast structural changes in condensed matter which are studied by ultrafast x-ray techniques. The generation and characterization of ultrashort hard x-ray pulses are being combined with detecting and analyzing processes of structural change by x-ray diffraction and absorption. This research aims at a basic understanding of the relevant nonequilibrium processes occurring on a time scale between 10 fs and 10 ps and the underlying microsopic mechanisms. In this way, relationships between structure and function of the systems investigated will be elucidated.Photoinduced ultrafast phase transitions, e.g., from the solid to the liquid phase and/or between different crystalline structures, as well as the dynamics of crystal lattices, e.g., the propagation of phonon wave packets or shock waves, are studied in metals, semiconductors, and semiconductor nanostructures. Reversible or irreversible changes of atomic position are directly monitored by time-resolved x-ray diffraction. Such experiments are combined with theoretical simulations of the microscopic structural changes. In crystallized macromolecules, i.e. biopolymers, chromopeptides and proteins, elementary steps of (bio)chemical reactions are studied, in disordered systems, e.g., the liquid phase, transient structures under the influence of the environment. Research on laser based compact sources for ultrashort x-ray pulses and new concepts for x-ray targets and optical components represents an important aspect of this work which is worked on in close collaboration of the groups participating in the priority programme.