Nonlinear phenomena in solid state physics and technology

Stationary waves in nonlinear, nondispersive systems, represented by an ideal crystalline solid, are discussed. Emphasis is placed on the effects of material structure and microstructure on the generation of the stationary waveform and on the thermal expansivity of the material. The relationship between the thermal expansivity of the crystal and the modal acoustic radiation-induced static strains generated by radiation sources associated with the vibrating atoms of the crystalline lattice is derived. The effects of dispersion in material systems, as represented by amorphous solid vitreous silica (glass), are considered. The introduction of dispersion into the nonlinear wave equation results in stationary wave solutions that have the form of solitary waves or solitons. In vitreous silica the solitons have a negative polarity, and are discussed in terms of their possible role in the negative thermal expansivity of glass at low temperatures.<>