Uncovering the mechanism of dynamics in metallic glass-forming liquids based on local symmetry entropy

Molecular dynamics simulations were performed to investigate the relationship of structure-dynamics in metallic glass-forming liquids. Fundamentally, it is found the degree of local symmetry plays an important role in the dynamics of glass-forming liquids. The local symmetry entropy is proposed and used for quantifying the degree of local symmetry. Local symmetry entropy is related to the rearrangements of a cage and translational diffusion. Particularly, the diffusion coefficient of metallic glass-forming liquids can be described by a local symmetry entropy scaling. Further exploration shows local symmetry entropy has a well linear correlation with two-pair entropy, suggesting that the decrease of symmetry entropy can contribute to the decrease of thermodynamic entropy in undercooled liquids in the cooling process. (paper)