The role of local-geometrical-orders on the growth of dynamic-length-scales in glass-forming liquids

TL;DR

This paper investigates how the growth of icosahedral local geometrical order influences the increase of dynamic length scales during the slowdown of atomic dynamics in metallic glass-forming liquids, shedding light on vitrification.

Contribution

It establishes a direct link between icosahedral ordering and the growth of dynamic length scales in metallic glasses, highlighting the role of local geometrical structures in glass transition.

Findings

Growth of icosahedral order correlates with increased dynamic length scale.

Transient icosahedral ordering may be the origin of dynamic length scales.

Structural relaxation is connected to local geometrical order growth.

Abstract

The precise nature of complex structural relaxation as well as an explanation for the precipitous growth of relaxation time in cooling glass-forming liquids are essential to the understanding of vitrification of liquids. The dramatic increase of relaxation time is believed to be caused by the growth of one or more correlation lengths, which has received much attention recently. Here, we report a direct link between the growth of a specific local-geometrical-order and an increase of dynamic-length-scale as the atomic dynamics in metallic glass-forming liquids slow down. Although several types of local geometrical-orders are present in these metallic liquids, the growth of icosahedral ordering is found to be directly related to the increase of the dynamic-length-scale. This finding suggests an intriguing scenario that the transient icosahedral ordering could be the origin of the dynamic-length-scale in metallic glass-forming liquids.