Local connectivity modulates multi-scale relaxation dynamics in a metallic glass-forming system

TL;DR

This study reveals how local atomic connectivity influences both short-term vibrational and long-term relaxation dynamics in metallic glass-forming systems, establishing a structural link between fast and slow atomic motions.

Contribution

It demonstrates that local connectivity acts as a structural parameter controlling vibrational excitations and relaxation behavior, providing new insights into the atomic-level origins of glass dynamics.

Findings

Local connectivity modulates vibrational excitations of particles.

It changes the relaxation dynamics from stretched to compressed exponential.

Long-time dynamics are linked to short-time vibrational behavior.

Abstract

The structural description for the intriguing link between the fast vibrational dynamics and slow diffusive dynamics in glass-forming systems is one of the most challenging issues in physical science. Here, in a model of metallic supercooled liquid, we find that local connectivity as an atomic-level structural order parameter tunes the short-time vibrational excitations of the icosahedrally coordinated particles and meanwhile modulates their long-time relaxation dynamics changing from stretched to compressed exponentials, denoting a dynamic transition from subdiffusive to hyperdiffusive motions of such particles. Our result indicates that long-time dynamics has an atomic-level structural origin which is related to the short-time dynamics, thus suggests a structural bridge to link the fast vibrational dynamics and the slow structural relaxation in glassy materials.