DODECAGONAL TA-TE QUASICRYSTALS WITH SIMILAR DIFFRACTION INTENSITIES

摘要

A development of necessary softwares and an accumulation of our experiences for the structure refinement of quasicrystals enabled us to determine detailed structures of quasicrystals.[l] On the other hand, another difficulty still exists. The structure refinement requires the use of so called phason temperature factor. This suggests that an atom or cluster arrangement has randomness to some extent and this is considered to be due to the existence of random phason. However, such a structure with the random phason gives diffraction intensities similar to those of models with fractal OD's, which has no random phason. This paper shows that two distinct structures with complicated OD's give quite similar diffraction intensities to each other and to a model with random phason. This means that the conventional diffraction experiment is practically impossible to distinguish the difference of these models. We demonstrate this in the case of dodecagonal Ta-Te quasicrystals.