PHONON-DISPERSION IN METALLIC-GLASS MG70ZN30

Analytical expressions for the phonon frequencies of a binary metallic glass, employing a simple model approach, are derived both for longitudinal and transverse branches of phonon frequencies. Our model assumes a central force, effective between the nearest neighbours, and a volume-dependent force. The computation of the phonon frequencies of the longitudinal and transverse phonons in Mg70Zn30 glass is carried out 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 obtained by molecular dynamics and neutron inelastic scattering for the longitudinal branch for few momentum transfers near the first peak of static structure factor.