2016/02/12 by Kirill V. Mitrofanov, Paul Fons, Kotaro Makino +16 · 32 citations
Materials Science · Physics and Astronomy · #Chemical and Physical Properties of Materials #Excitation #Femtosecond #Laser #Lattice (music) #Metastability #Nanoscopic scale #Phase-change materials and chalcogenides #Picosecond #Pulsed laser #Thermal #Transition Metal Oxide Nanomaterials #cond-mat.mtrl-sci
paper · pdf · doi:10.1038/srep20633
published in Scientific Reports 6(1), 20633 (Nature Portfolio) · 8 pages, 4 figures
openalex publication_date 2016/02/12 · openalex created_date 2016/06/24 · arxiv created 2017/05/26 · arxiv updated 2017/05/29 · openalex updated_date 2026/08/05
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 Ge2Sb2Te5 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 of the switching process, ultimately leading to a redefined speed limit, and improved energy efficiency and reliability of phase-change memory technologies.