Low-frequency vibrational properties and structure correlation in metallic glass

Abstract

Molecular dynamic simulations were carried out to study the characteristics of the vibrational modes and structural correlation in Cu50Zr50 metallic glass. The participation ratio and the 3-dimensional eigenvector fields were analyzed to study the vibrational characteristics. The modes at low frequency with high participation ratio values show significant plane wave character, whereas the low participation ratio modes show vortex structures, consisting of localized structures embedded in a plane-wave-like background. Furthermore, the low-frequency modes with small participation ratio show strong anharmonicity which is closely correlated to the weight of the localized component in these modes. Our results also manifest that the boson peak has no direct correlation with anharmonicity and may be directly controlled by the five-fold local symmetry in local structures. These findings provide useful understanding of the vibrational properties in metallic glasses.