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Femtosecond x-ray diffraction reveals a liquid–liquid phase transition in phase-change materials

Zalden, Peter ; Quirin, Florian ; Schumacher, Mathias ; Siegel, Jan ; Wei, Shuai ; Koc, Azize ; Nicoul, Matthieu ; Trigo, Mariano ; Andreasson, Pererik LU and Enquist, Henrik LU , et al. (2019) In Science 364(6445). p.1062-1067
Abstract

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... (More)

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.

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type
Contribution to journal
publication status
published
subject
in
Science
volume
364
issue
6445
pages
6 pages
publisher
American Association for the Advancement of Science
external identifiers
  • scopus:85067625790
ISSN
0036-8075
DOI
10.1126/science.aaw1773
language
English
LU publication?
yes
id
5b81bf10-96fb-4ad5-bcab-20b1c5d25bde
date added to LUP
2019-07-04 17:10:07
date last changed
2019-11-20 05:49:57
@article{5b81bf10-96fb-4ad5-bcab-20b1c5d25bde,
  abstract     = {<p>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 Ag<sub>4</sub>In<sub>3</sub>Sb<sub>67</sub>Te<sub>26</sub> and Ge<sub>15</sub>Sb<sub>85</sub> 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.</p>},
  author       = {Zalden, Peter and Quirin, Florian and Schumacher, Mathias and Siegel, Jan and Wei, Shuai and Koc, Azize and Nicoul, Matthieu and Trigo, Mariano and Andreasson, Pererik and Enquist, Henrik and Shu, Michael J. and Pardini, Tommaso and Chollet, Matthieu and Zhu, Diling and Lemke, Henrik and Ronneberger, Ider and Larsson, Jörgen and Lindenberg, Aaron M. and Fischer, Henry E. and Hau-Riege, Stefan and Reis, David A. and Mazzarello, Riccardo and Wuttig, Matthias and Sokolowski-Tinten, Klaus},
  issn         = {0036-8075},
  language     = {eng},
  number       = {6445},
  pages        = {1062--1067},
  publisher    = {American Association for the Advancement of Science},
  series       = {Science},
  title        = {Femtosecond x-ray diffraction reveals a liquid–liquid phase transition in phase-change materials},
  url          = {http://dx.doi.org/10.1126/science.aaw1773},
  doi          = {10.1126/science.aaw1773},
  volume       = {364},
  year         = {2019},
}