  We report a metadynamics simulation study of crystallization in a deep
undercooled metallic glass-forming liquid by developing appropriate collective
variables. Through a combined analysis of free energy surface (FES) and
atomic-level behaviors, a picture of an abnormal-endothermic crystallization
process is revealed: rejuvenated disorder states with less local
fivefold-symmetry and fast dynamics form firstly by changing the local chemical
order around Cu atoms, which then act as the precursor for the nucleation of
well-ordered crystallites. This process reflects a complex energy landscape
with well-separated glassy and crystal basins, giving rise to the direct
evidence of intrinsic frustration against crystallization in deep undercooled
metallic glass forming liquids. Moreover, the rejuvenated disorder states with
distinct physical behaviors offer great opportunities to tailor the
performances of metallic glass by controlling the thermal history of a metallic
melt.
