STRUCTURE AND ANOMALOUS VIBRATIONS OF AN Al-Ni-Co IDEAL QUASICRYSTAL STUDIED BY ATOMIC-RESOLUTION HAADF-STEM

摘要

Quasicrystals with symmetries forbidden to ordinary crystals have now been firmly established as a new form of solid. The central issues have been where atoms are in such a non-periodic structure and why a quasiperiodicity is forced at certain conditions. The decagonal quasicrystals are built up by a periodic stacking of quasiperiodic planes (two-dimensional quasicrystal), so that the atomic-resolution imaging along the tenfold symmetry axis provides a direct interpretation of the quasiperiodic atomic structure.