Dynamics of the AlPdMn icosahedral phase

Dynamics of the icosahedral phase AlPdMn has been investigated with a centimetre size single grain and using inelastic neutron scattering measurements. Well defined acoustic modes have been observed close to strong Bragg reflections. Phonons broaden significantly as wavevectors exceed 0.35 A−1. Broad (1 THz) dispersionles excitations also show up with energies close to 1.8, 3.4 and 5.8 THz, some of them being associated to crossing with quasi-Brillouin zone boundaries.