Triple-axis neutron-scattering study of phason dynamics in Al-Mn-Pd quasicrystals

We present an extensive triple-axis neutron-scattering study of phason hopping in a single-domain sample of a perfect icosahedral ${\mathrm{Al}}_{70.4}{\mathrm{Mn}}_{8.6}{\mathrm{Pd}}_{21.0}$ quasicrystal. The quasielastic intensities exhibit important anisotropies. They are compared with models at various levels of sophistication. This comparison strongly suggests the occurrence of simultaneous correlated jumps. The important correlations are directed along the threefold axes.