Phonon dispersion in Zr–Ti–Cu–Ni–Be bulk metallic glasses

Analytical expressions for the phonon frequencies of Zr–Ti–Cu–Ni–Be bulk metallic glasses (BMGs) both for longitudinal and transverse phonon modes based on a simple-model approach have been presented. The model assumes a central force, effective between the nearest neighbours, and a volume-dependent force. Both types of excitations of phonons are computed for the Zr–Ti–Cu–Ni–Be BMGs for the first time both for self-consistent screening of conduction electrons with and without the inclusion of correlation effects. Phonon frequency expressions reproduce the main characteristic features of the dispersion curves. The results obtained for these systems have been compared with the other theoretical results and experimental data available for different quaternary glassy systems. A brief discussion on the similarity of dispersion curves of these glasses in terms of their topological similarity is also given.