The critical model size for simulating the structure-dynamics correlation in bulk metallic glasses

Abstract

Computational simulation provides an effective way of understanding the disordered structure and structure-property relationships for metallic glass systems. Here, we systematically investigated the finite-size effects of the static structure and dynamical behaviors in a three-dimensional Cu50Zr50 model metallic glass via classical molecular dynamics (MD) simulations. It was found that the local structure is insensitive to the system size while the dynamical properties present evident finite-size effects. The decoupling between local structure and relaxation dynamics in the investigated supercooling emerges when the system contains less than ~2000 atoms. However, the collapse can be observed between the structural relaxation time and the dynamical heterogeneity for different sized systems across the whole range of our investigation. Our results support the intrinsic link between the structural relaxation time and dynamic heterogeneity and reveal the critical simulated system size for representing the structural origins of dynamics in bulk metallic glass with ignorable surface effects.