Femtosecond x-ray diffraction reveals a liquid–liquid phase transition in phase-change materialsI. Physikalisches Institut and JARA-FIT, RWTH Aachen, Aachen, Germany.
Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Duisburg, Germany & Institut für Physik und Astronomie, Universität Potsdam, Potsdam, Germany.
Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Duisburg, Germany.
Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, USA & Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, USA.
Department of Applied Physics, Stanford University, Stanford, USA.
Lawrence Livermore National Laboratory, Livermore, USA.
Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, USA.
Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, USA.
Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, USA & Paul Scherrer Institute, Villigen, Switzerland.
Department of Physics, Lund University, Lund, Sweden.
Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, USA & Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, USA & Department of Materials Science and Engineering, Stanford University, Stanford, USA.
Institut Laue-Langevin, Grenoble, France.
Lawrence Livermore National Laboratory, Livermore, USA.
Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, USA & Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, USA.
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2019 (English)In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 364, no 6445, p. 1062-1067Article in journal (Refereed) Published
Abstract [en]
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. © 2019 American Association for the Advancement of Science.
Place, publisher, year, edition, pages
Washington, DC: American Association for the Advancement of Science , 2019. Vol. 364, no 6445, p. 1062-1067
National Category
Condensed Matter Physics
Identifiers
URN: urn:nbn:se:hh:diva-39862DOI: 10.1126/science.aaw1773ISI: 000471306700040PubMedID: 31197008Scopus ID: 2-s2.0-85067625790OAI: oai:DiVA.org:hh-39862DiVA, id: diva2:1327132
2019-06-192019-06-192025-10-01Bibliographically approved