Berlin 2015 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 38: Phase change/ resistive switching

DS 38.4: Vortrag

Donnerstag, 19. März 2015, 15:45–16:00, H 0111

Optical and structural dynamics of the photoinduced phase transition of GST — •Lutz Waldecker¹, Timothy Miller², Roman Bertoni¹, Simon Wall², and Ralph Ernstorfer¹ — ¹Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany — ²ICFO - Institut de Ciències Fotòniques, Castelldefels (Barcelona), Spain

The phase change material Ge₂Sb₂Te₅ (GST) exhibits large changes in its optical and electronic properties across the structural phase transition between its amorphous and crystalline states. We use single-shot optical and diffraction measurements to follow the system*s dynamics after initiating the phase transition with a femtosecond laser pulse. We observe large changes in the dielectric function instantaneously after photoexcitation, when the lattice still shows long-range order. Energy transfer from electrons to the lattice heats leads to melting on a few picosecond timescale and the amorphization is achieved by thermal processes on longer timescales.