Simulation of field-ion-microscope images for the Al-Mn icosahedral phase

Simulations of field-ion-microscope images for the icosahedral phase of Al-Mn, based on new structural models, are presented and compared to the experimentally observed image features. Closest agreement thus far is found for a cubic model having a 3·32 nm unit cell edge and containing a MacKay-icosahedron inner motif, with all of the manganese sublattice and only some of the aluminum atoms contributing to the computed images. An octahedral-motif decoration of a perfect three-dimensional Penrose tiling has also been constructed for comparison.