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7 5 I H I G H L I G H T S 2 0 2 3

PRINCIPAL PUBLICATION AND AUTHORS

Pressure-induced nonmonotonic cross-over of steady relaxation dynamics in a metallic glass, X. Zhang (a), H. Lou (a), B. Ruta (b), Y. Chushkin (c), F. Zontone (c), S. Li (b), D. Xu (a), T. Liang (a), Z. Zeng (a), H. Mao (a), Q.S. Zeng (a), Proc. Natl. Acad. Sci., 120, e2302281120 (2023); https:/doi.org/10.1073/pnas.2302281120 (a) Center for High Pressure Science and Technology Advanced Research, Pudong, Shanghai (China) (b) Université Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, Lyon (France) (c) ESRF

REFERENCES

[1] Q.S. Zeng, MRE 8, 028101 (2023). [2] Q.S. Zeng et al., Phys. Rev. Lett. 104, 105702 (2010). [3] Q.S. Zeng et al., Science 332, 1404 (2011). [4] H. Lou et al., Nat. Commun. 11, 314 (2020). [5] Q.S. Zeng et al., Proc. Natl. Acad. Sci. 113, 1714 (2016).

the experimental observation at the beginning that the collective atomic motion initially slows down below ~3 GPa with increasing density in the Ce68Al10Cu20Co2 MG. Then, counter-intuitively, it accelerates with further compression, showing an unusual non-monotonic pressure-induced steady relaxation dynamics crossover at ~3 GPa. Moreover, this relaxation dynamics closely correlates with the dramatic changes in local atomic structures during compression through the pressure- induced polyamorphic transition revealed by X-ray diffraction (XRD), which indicates that, besides overall density, structural details could also play an essential role in glass relaxation dynamics.

These findings demonstrate that there is a close relationship between glass relaxation dynamics and atomic structures in MGs. The in-situ, high-pressure wide- angle XPCS technique can also be extended to explore the relationship between relaxation dynamics and atomic structures in various glasses, especially those significantly tuneable by compression, offering new opportunities for glass atomic relaxation dynamics studies at extreme conditions.

Fig. 56: Atomic relaxation time (t) as a function of pressure of the Ce68Al10Cu20Co2 metallic glass sample loaded in a DAC obtained by in-situ, high-pressure XPCS. The insets are two-time intensity correlation function (TTCF), in which the width of the reddish diagonal contour is proportional to the relaxation time.