Title: Local connectivity modulates multi-scale relaxation dynamics in a metallic glass-forming system,
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.