Onset of Cooperative Dynamics in an Equilibrium Glass-Forming Metallic Liquid

Onset of cooperative dynamics has been observed in many molecular liquids, colloids, and granular materials in the metastable regime on approaching their respective glass or jamming transition points, and is considered to play a significant role in the emergence of the slow dynamics. However, the nature of such dynamical cooperativity remains elusive in multicomponent metallic liquids characterized by complex many-body interactions and high mixing entropy. Herein, we report evidence of onset of cooperative dynamics in an equilibrium glass-forming metallic liquid (LM601: Zr₅₁Cu₃₆Ni₄Al₉). This is revealed by deviation of the mean effective diffusion coefficient from its high-temperature Arrhenius behavior below T_A 1300 K, i.e., a crossover from uncorrelated dynamics above T_A to landscape-influenced correlated dynamics below T_A. Furthermore, the onset/crossover temperature T_A in such a multicomponent bulk metallic glass-forming liquid is observed at approximately twice of its calorimetric glass transition temperature (T_g 697 K) and in its stable liquid phase, unlike many molecular liquids.