Upon cooling, glass-forming liquids experience a two-step relaxation associated to the cage rattling and the escape from the cage, and the following decoupling between the \b{eta}- and the {\alpha}-relaxations. The found decoupling behaviors have greatly changed the face of glassy physics and materials studies. Here we report a novel dynamic decoupling that the relaxation function changes gradually from a single-step to a two-step form as temperature declines through the stress relaxation of various metallic glasses in a broad time and temperature range below glass transition temperature (Tg). Such a two-step relaxation is unexpected in glassy state and reveals a decoupling of dynamic modes arising from two different mechanisms: a faster one exhibiting ballistic-like feature, and a slower one associated with a broader distribution of relaxation times typical of subdiffusive atomic motion. This first observation of two-step dynamics in metallic glassy state points to a far richer-than-expected scenario for glass relaxation.
@article{arxiv.1609.09611,
title = {Relaxation decoupling in metallic glassy state},
author = {P. Luo and P. Wen and H. Y. Bai and B. Ruta and W. H. Wang},
journal= {arXiv preprint arXiv:1609.09611},
year = {2017}
}
Comments
20 pages (18 pages for the main text and 2 pages for the supplementary information), 7 figures (4 figures in the main text and 3 figures in the supplementary information)