J. Phys. IV France 02 (1992) C2-279-C2-283
The origin of the anomalous low-frequency vibrational behaviour of amorphous solidsS. R. ELLIOTT
Laboratoire de Science des Matériaux Vitreux, Université de Montpellier II, Place Eugène Bataillon, 34095 Montpellier Cedex, France
The anomalous vibrational behaviour exhibited by non-crystalline materials - a peak in the vibrational density of states, and in the Raman spectrum (the boson peak) at low frequencies, and a peak in the heat capacity and a plateau in the thermal conductivity at low temperatures - is ascribed ta phonon localization associated with the strong scattering of phonons by density-fluctuation domains in the structure. Within such domains, short-range and medium-range arder is maintained, and outside them the material is structurally homogeneous and isotropie. This model can also explain the correlation between the boson-peak frequency and the position of the first sharp diffraction peak in the structure factor observed in a number of inorganie and polymerie amorphous solids.
© EDP Sciences 1992