Regensburg 2013 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 78: Surface Dynamics I
O 78.13: Vortrag
Donnerstag, 14. März 2013, 19:00–19:15, H42
Switching dynamics in laser-driven phase change materials probed by time-resolved X-ray diffraction — •Florian Quirin1, Azize Koc1, Matthieu Nicoul1, Peter Zalden2, Jan Siegel3, Mariano Trigo4, Pererik Andreasson5, Henrik Enquist5, Michael Shu4, Tommaso Pardini6, Matthieu Chollet7, Diling Zhu7, Henrik Lemke7, Aaron Lindenberg4, David Reis4, Jörgen Larsson5, Stefan Hau-Riege6, Matthias Wuttig2, and Klaus Sokolowski-Tinten1 — 1University of Duisburg-Essen, Germany — 2RWTH Aachen, Germany — 3CSIC, Madrid, Spain — 4PULSE@SLAC, USA — 5Lund University, Sweden — 6LLNL, Livermore, USA — 7SLAC, Menlo Park USA
Phase change materials (PCMs) exhibit rapid and reversible phase transitions between an amorphous and a crystalline state, which can be triggered by short light pulses. Since the structural changes are associated with large differences in the optical properties of the two phases, PCMs are widely used in rewritable optical data storage technology (e.g. RW-DVDs). We have used time-resolved X-ray scattering at the Linear Coherent Light Source (LCLS) to directly probe the structural dynamics in PCMs (GeSb, GST, AIST) after fs laser irradiation over an extended time range from fs to μs, thus obtaining complete information on the phase transition dynamics. All transitions (amorphous-to-crystalline and vice versa) seem to involve melting of the material. Depending on the excitation strength melting can occur on a sub-ps time-scale as a non-thermal process. However, it takes ns up to μs for the material to resolidify and to reach the final state.