Electron density of icosahedral Zn-Mg-Y quasicrystals determined by a six-dimensional maximum entropy method

摘要

The maximum entropy method (MEM) in six-dimensional space was applied to the crystal structure determination of a newly found Zn-Mg-Y quasicrystal with superspace group Fm 35. This has a prominent character in the electron density map. Large occupation domains are located at vertex, edge-centre and body-centre positions of the icosahedral lattice similar to Al-Cu-Li but they have a complicated shape. The map shows strong peaks at small areas in the domains at the even-parity vertex and edge centre, leading to a completely new structure. The application of the similarity transformation to the calculation of the electron density map by MEM is discussed.