Thermal phason fluctuation in an Al–Cu–Co decagonal quasicrystal

Abstract In situ high-temperature, high-resolution transmission electron microscopy (HRTEM) has been performed on an Al–Cu–Co decagonal quasicrystal, to investigate thermal phason fluctuations. The changing tiling pattern with elapsed time in the HRTEM image has been analyzed, and the spatial and temporal variations of the phason field have been deduced. In the temporal variation, abrupt and discrete changes have been observed in addition to smooth and continuous ones. The degrees of the spatial and temporal correlations of the phason fluctuation have been evaluated, both of which decrease continuously with increasing distance and time, respectively. The results have been discussed in light of the random tiling model of the quasicrystal.