Abstract

Solitary Surface Acoustic Waves

A.Mayer (Institute for Theoretical Physics, University of Regensburg, Regensburg, Germany); A.M.Lomonosov (General Physics Institute, Moscow, Russia); P.Hess (Institute of Physical Chemistry, University of Heidelberg, Heidelberg, Germany); C.Eckl (Infineon Technologies AG, Munich, Germany); A.S.Kovalev (Verkin Institute for Low Temperature Physics and Engineering, Kharkov, Ukraine)

e-mail: andreas.mayer@physik.uni-regensburg.de

In the presence of linear dispersion, the equations of nonlinear elasticity theory admit solutions that correspond to solitary waves propagating along the surface of a semi-infinite solid. Their existence has been verified experimentally for quartz and crystalline silicon substrates by laser excitation of high-intensity strain pulses. Normal and anomalous dispersion have been generated by coating the substrate. The resulting solitary pulse shapes were observed by an optical detection scheme. The propagation of nonlinear surface waves in solids is governed by an evolution equation containing a nonlocal nonlinearity of second order. On the basis of this equation, stationary pulse shapes have been computed which agree very well with the corresponding experimental pulses. In numerical simulations, pulse collisions are investigated for different dispersion laws that result from the specific acoustic mismatch between film and substrate. Solitary waves at a solid-liquid interface and nonlinear long wave - short wave interaction in layered structures will also be discussed.

Section : 1