A decagonal quasicrystal with rhombic and hexagonal tiles decorated with icosahedral structural units

W Z Wang; X Z Zhou; Z Q Yang; Y Qi; H Q Ye

doi:10.1107/S2052252520004297

A decagonal quasicrystal with rhombic and hexagonal tiles decorated with icosahedral structural units

IUCrJ. 2020 Apr 23;7(Pt 3):535-541. doi: 10.1107/S2052252520004297. eCollection 2020 May 1.

Authors

W Z Wang^{1

2}, X Z Zhou², Z Q Yang², Y Qi¹, H Q Ye²

Affiliations

¹ School of Materials Science and Engineering, Northeastern University, Shenyang 110819, People's Republic of China.
² Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Science, Shenyang 110016, People's Republic of China.

Abstract

The structure of a decagonal quasicrystal in the Zn₅₈Mg₄₀Y₂ (at.%) alloy was studied using electron diffraction and atomic resolution Z-contrast imaging techniques. This stable Frank-Kasper Zn-Mg-Y decagonal quasicrystal has an atomic structure which can be modeled with a rhombic/hexagonal tiling decorated with icosahedral units at each vertex. No perfect decagonal clusters were observed in the Zn-Mg-Y decagonal quasicrystal, which differs from the Zn-Mg-Dy decagonal crystal with the same space group P10/mmm. Y atoms occupy the center of 'dented decagon' motifs consisting of three fat rhombic and two flattened hexagonal tiles. About 75% of fat rhombic tiles are arranged in groups of five forming star motifs, while the others connect with each other in a 'zigzag' configuration. This decagonal quasicrystal has a composition of Zn_68.3Mg_29.1Y_2.6 (at.%) with a valence electron concentration (e/a) of about 2.03, which is in accord with the Hume-Rothery criterion for the formation of the Zn-based quasicrystal phase (e/a = 2.0-2.15).

Keywords: Penrose tiling; decagonal quasicrystals; electron diffraction; icosahedrons; scanning-transmission electron microscopy.

Grants and funding

This work was funded by National Nature Science Foundation of China grants 51771202 and 51971225. Key Research Program of Frontier Science, CAS grant QYZDY- SSW-JSC207.