Surface phonons in both periodic and Fibonacci Nb/Cu metallic superlattice systems have been studied by means of the Brillouin light-scattering technique. Measurement of the phase velocity of the surface Rayleigh wave enabled us to compare the elastic properties of these two types of structures with those calculated from the elastic constants of bulk Cu and Nb. The results obtained have shown that the relevant parameter for determining the elastic behavior of quasiperiodic Fibonacci superlattices is the average distance between Nb/Cu interfaces, rather than the quasiperiodicity, which is the governing parameter in x-ray and structural analysis.

• Received 13 July 1992

DOI:https://doi.org/10.1103/PhysRevB.46.12777