Density of vibrational states in highly disordered systems through Raman scattering and atomic-scale simulation

Abstract

Raman scattering is used as a probe with regard to the understanding of local structural arrangements and correlated lattice dynamics in highly disordered systems. This investigation is shown to be particularly fruitful if one records the signal over a very wide frequency range (including Stokes, anti-Stokes and multiple-order processes). Results on amorphous semiconductors and vitreous materials are discussed in comparison with those obtained by other techniques (inelastic neutron scattering) or numeric simulations (valence-force-field or molecular dynamics approaches). It is shown that the dynamic response of a disordered material is essentially accounted for by simply considering the lattice dynamics of its crystalline counterpart.