Correlated simultaneous phason jumps in an icosahedral Al-Mn-Pd quasicrystal

A triple-axis neutron-scattering experiment has been performed on a large single-grain sample of an icosahedral Al-Mn-Pd quasicrystal. The scattering plane in reciprocal space was a binary plane of the quasicrystal. The intensities of the quasielastic signals collected were compared with model calculations assuming isolated single-particle jumps along two-, three-, and fivefold axes of the quasicrystal. The agreement turned out to be unsatisfactory. We were able to explain the: experimental data only by assuming the existence of correlated simultaneous jumps of several atoms.