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Phase-change materials based on Ge-Sb-Te alloys are widely used in industrial applications such as nonvolatile memories, but reaction pathways for crystalline-to-amorphous phase-change on picosecond timescales remain unknown. Femtosecond laser excitation and an ultrashort x-ray probe is used to show the temporal separation of electronic and thermal effects in a long-lived (> 100 ps) transient metastable state of Ge 2 Sb 2 Te 5 with muted interatomic interaction induced by a weakening of resonant bonding. Due to a specific electronic state, the lattice undergoes a reversible nondestructive modification over a nanoscale region, remaining cold for 4 ps. An independent time-resolved x-ray absorption fine structure experiment confirms the existence of an intermediate state with disordered bonds. This newly unveiled effect allows the utilization of non-thermal ultra-fast pathways enabling artificial manipulation …
Nature Publishing Group
Publication date: 
12 Feb 2016

Kirill V Mitrofanov, Paul Fons, Kotaro Makino, Ryo Terashima, Toru Shimada, Alexander V Kolobov, Junji Tominaga, Valeria Bragaglia, Alessandro Giussani, Raffaella Calarco, Henning Riechert, Takahiro Sato, Tetsuo Katayama, Kanade Ogawa, Tadashi Togashi, Makina Yabashi, Simon Wall, Dale Brewe, Muneaki Hase

Biblio References: 
Volume: 6 Issue: 1 Pages: 1-9
Scientific reports