Structure of Al-Li-Cu Icosahedral Crystals and Penrose Tiling

摘要

We report synchrotron x ray powder diffraction measurements of the Aluminum Lithium Copper icosahedral phase. Our results are found to be in agreement with the computed diffraction intensities of the three dimensional Penrose tiling when Al and Cu atoms are randomly positioned at the vertices and edge centers of the unit cells. Comparison is also made with a similarly decorated icosahedral structure constructed by dense packing of icosahedra; the agreement is less satisfactory.