TY - JOUR
T1 - Sub-nanometre resolution of atomic motion during electronic excitation in phase-change materials
AU - Mitrofanov, Kirill V.
AU - Fons, Paul
AU - Makino, Kotaro
AU - Terashima, Ryo
AU - Shimada, Toru
AU - Kolobov, Alexander V.
AU - Tominaga, Junji
AU - Bragaglia, Valeria
AU - Giussani, Alessandro
AU - Calarco, Raffaella
AU - Riechert, Henning
AU - Sato, Takahiro
AU - Katayama, Tetsuo
AU - Ogawa, Kanade
AU - Togashi, Tadashi
AU - Yabashi, Makina
AU - Wall, Simon
AU - Brewe, Dale
AU - Hase, Muneaki
N1 - Funding Information:
This work was supported by X-ray Free Electron Laser Priority Strategy Program, entitled Lattice dynamics of phase change materials by time-resolved X-ray diffraction (NO. 12013011 and 12013023), from the Ministry of Education, Culture, Sports, Science and Technology of Japan. The XFEL experiments were performed at the BL3(EH2) of SACLA with the approval of the Japan Synchrotron Radiation Research Institute (JASRI) (Proposal No. 2012B8041, 2013A8051, 2013B8056, 2014A8039 and 2014B8061). Sector 20 facilities at the Advanced Photon Source, and research at these facilities, are supported by the US Department of Energy - Basic Energy Sciences, the Canadian Light Source and its funding partners, the University of Washington, and the Advanced Photon Source. Use of the Advanced Photon Source, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science by Argonne National Laboratory, was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357.
PY - 2016/2/12
Y1 - 2016/2/12
N2 - 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.
AB - 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.
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U2 - 10.1038/srep20633
DO - 10.1038/srep20633
M3 - Article
AN - SCOPUS:84958074045
SN - 2045-2322
VL - 6
JO - Scientific Reports
JF - Scientific Reports
M1 - 20633
ER -
