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