Liquid-like atoms in dense-packed solid glasses

Revealing the microscopic structural and dynamic pictures of glasses is a long-standing challenge for scientists(1,2). Extensive studies on the structure and relaxation dynamics of glasses have constructed the current classical picture(3-5): glasses consist of some 'soft zones' of loosely bound atoms embedded in a tightly bound atomic matrix. Recent experiments have found an additional fast process in the relaxation spectra(6-9), but the underlying physics of this process remains unclear. Here, combining extensive dynamic experiments and computer simulations, we reveal that this fast relaxation is associated with string-like diffusion of liquid-like atoms, which are inherited from the high-temperature liquids. Even at room temperature, some atoms in dense-packed metallic glasses can diffuse just as easily as they would in liquid states, with an experimentally determined viscosity as low as 10(7) Pa.s. This finding extends our current microscopic picture of glass solids and might help establish the dynamics-property relationship of glasses(4).

Automated summary

This paper introduces the current status of research on the microscopic structure and dynamic picture of glasses, and discusses a new fast relaxation process. The study found that this fast relaxation is related to the string-like diffusion of liquid-like atoms.