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Revealing Dynamic Processes of Materials in Liquids Using Liquid Cell Transmission Electron Microscopy
Published on: December 20, 2012
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La difracción de rayos X en femtosegundos revela una transición de fase líquido-líquido en materiales de cambio de
Peter Zalden1,2,3, Florian Quirin4, Mathias Schumacher5
1Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, CA 94025, USA. klaus.sokolowski-tinten@uni-due.de peter.zalden@xfel.eu.
Science (New York, N.Y.)
|June 15, 2019
Resumen
Los investigadores descubrieron una transición de fase líquido-líquido en materiales de cambio de fase utilizando difracción y simulaciones avanzadas de rayos X. Este descubrimiento vincula la estructura atómica con la cinética de conmutación de memoria, lo que permite la optimización de los dispositivos de memoria de cambio de fase.
Área de la Ciencia:
- Ciencias de los materiales
- Física de la materia condensada
- Química computacional
Sus antecedentes:
- Los dispositivos de memoria de cambio de fase (PCM) utilizan materiales que cambian entre los estados vidrioso y cristalino.
- La cinética de la cristalización es crucial para la tecnología PCM, pero sigue siendo poco comprendida a nivel atómico.
Objetivo del estudio:
- Para resolver las transiciones a escala atómica en los materiales de cambio de fase durante la extinción de fusión y la cristalización.
- Para aclarar la relación entre la estructura atómica y la cinética de las transiciones de fase.
Principales métodos:
- La difracción de rayos X de femtosegundos (fsXRD) se empleó para sondear la dinámica atómica.
- Se utilizaron simulaciones por computadora ab initio para modelar la función de correlación de pares dependiente del tiempo.
Principales resultados:
- Se identificó una transición de fase líquido-líquido en Ag4In3Sb67Te26 (a 660 K) y Ge15Sb85 (a 610 K).
- Esta transición es impulsada principalmente por el inicio de las distorsiones de Peierls.
- La amplitud de las distorsiones de Peierls se correlaciona con el aumento de la energía de activación para la difusión.
Conclusiones:
- Se estableció un vínculo directo entre la estructura atómica (distorsiones de Peierls) y la cinética del material (difusividad).
- Esta comprensión facilita la optimización sistemática de la cinética de conmutación en los materiales de memoria de cambio de fase.
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