TY  - JOUR
A1  - Zalden, Peter
A1  - Quirin, Florian
A1  - Schumacher, Mathias
A1  - Siegel, Jan
A1  - Wei, Shuai
A1  - Koc, Azize
A1  - Nicoul, Matthieu
A1  - Trigo, Mariano
A1  - Andreasson, Pererik
A1  - Enquist, Henrik
A1  - Shu, Michael J.
A1  - Pardini, Tommaso
A1  - Chollet, Matthieu
A1  - Zhu, Diling
A1  - Lemke, Henrik
A1  - Ronneberger, Ider
A1  - Larsson, Jörgen
A1  - Lindenberg, Aaron M.
A1  - Fischer, Henry E.
A1  - Hau-Riege, Stefan
A1  - Reis, David A.
A1  - Mazzarello, Riccardo
A1  - Wuttig, Matthias
A1  - Sokolowski-Tinten, Klaus
T1  - Femtosecond x-ray diffraction reveals a liquid-liquid phase transition in phase-change materials
JF  - Science
N2  - In phase-change memory devices, a material is cycled between glassy and crystalline states. The highly temperature-dependent kinetics of its crystallization process enables application in memory technology, but the transition has not been resolved on an atomic scale. Using femtosecond x-ray diffraction and ab initio computer simulations, we determined the time-dependent pair-correlation function of phase-change materials throughout the melt-quenching and crystallization process. We found a liquid-liquid phase transition in the phase-change materials Ag4In3Sb67Te26 and Ge15Sb85 at 660 and 610 kelvin, respectively. The transition is predominantly caused by the onset of Peierls distortions, the amplitude of which correlates with an increase of the apparent activation energy of diffusivity. This reveals a relationship between atomic structure and kinetics, enabling a systematic optimization of the memory-switching kinetics.
Y1  - 2019
U6  - https://doi.org/10.1126/science.aaw1773
SN  - 0036-8075
SN  - 1095-9203
VL  - 364
IS  - 6445
SP  - 1062
EP  - 1067
PB  - American Assoc. for the Advancement of Science
CY  - Washington, DC
ER  -