Phonon Traces In Glassy Vibrations

A numerical approach, based on a local comparative projectional analysis onto symmetry modes of elementary structural units of glasses and their crystalline counterparts, is developed and used for the analysis of atomic vibrations in glasses in terms of phonons for the entire frequency range. The results of such an analysis shed light on the origin of the modes in the controversial low-frequency range, including the boson-peak region. Comparative analyses undertaken for glass, lattice-glass, and polycrystalline models reveal the role of different types of disorder in atomic vibrations.