Depicting Defects in Metallic Glasses by Atomic Vibrational Entropy

XQ Lu and SD Feng and L Li and LM Wang and RP Liu, JOURNAL OF PHYSICAL CHEMISTRY LETTERS, 14, 6998-7006 (2023).

DOI: 10.1021/acs.jpclett.3c01674

Due to the chaotic structure of amorphous materials,it is challengingto identify defects in metallic glasses. Here we tackle this problemfrom a thermodynamic point of view using atomic vibrational entropy,which represents the inhomogeneity of atomic contributions to vibrationalmodes. We find that the atomic vibrational entropy is correlated tothe vibrational mean-square displacement and polyhedral volume ofatoms, revealing the critical role of vibrational entropy in bridgingdynamics, thermodynamics, and structure. On this method, the localvibrational entropy obtained by coarse-graining the atomic vibrationalentropy in space can distinguish more effectively between liquid-likeand solid-like atoms in metallic glasses and establish the correlationbetween the local vibrational entropy and the structure of metallicglasses, offering a route to predict the plastic events from localvibrational entropy. The local vibration entropy is a good indicatorof thermally activated and stress-driven plastic events, and its predictiveability is better than that of the structural indicators.

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