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arXiv · 2510.06409

Emergence of multiple relaxation processes during low to high density transition in Au49Cu26.9Si16.3Ag5.5Pd2.3 metallic glass

Alberto Ronca·Antoine Cornet·Jie Shen·Thierry Deschamps·Eloi Pineda·Yuriy Chushkin·Federico Zontone·Mohamed Mezouar·Isabella Gallino·Gaston Garbarino·Beatrice Ruta
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Abstract

The existence of multiple amorphous states, or polyamorphism, remains one of the most debated phenomena in disordered matter, particularly regarding its microscopic origin and impact on glassy dynamics. Profiting of the enhanced data quality provided by brilliant synchrotrons, we combined high pressure X-ray photon correlation spectroscopy and X-ray diffraction to investigate the atomic dynamics-structure relationship in a Au49Cu26.9Si16.3Ag5.5Pd2.3 metallic glass at room temperature. We identify a structural and dynamical crossover near 3 GPa, marked by avalanches-like massive atomic rearrangements that promote the system toward increasingly compact atomic cluster connections. This crossover superimposes to a pressure-induced acceleration of the atomic motion recently reported, and signals the onset of a transitional state, potentially linked to the nucleation of a new phase within the glass, characterized by the coexistence of two amorphous states with distinct relaxation processes. These results provide evidence for a sluggish, continuous polyamorphic transformation, even in absence of marked structural discontinuities.

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Alberto Ronca, Antoine Cornet, Jie Shen, Thierry Deschamps, Eloi Pineda, Yuriy Chushkin, Federico Zontone, Mohamed Mezouar, Isabella Gallino, Gaston Garbarino, Beatrice Ruta. 2025-10-07. Emergence of multiple relaxation processes during low to high density transition in Au49Cu26.9Si16.3Ag5.5Pd2.3 metallic glass. https://arxiv.org/abs/2510.06409

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