Ultrasonic propagation in quasicrystals and quasiperiodic structures

In many respects, quasicrystal and quasiperiodic structures have a status intermediate between periodic crystals and amorphous materials. Furthermore, new types of elastic excitations appear in such media. In this paper we examine some consequences of this original status on the elastic constants, the ultrasonic attenuation and the low temperature behaviour of quasicrystals. Experimental results illustrating these different aspects are reported