Berlin 2015 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 90: Phase change / resistive switching (DS with HL)
HL 90.4: 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.