The first metallic glass of Au-Si alloy has been discovered for over half a century, but its atomic structure is still puzzling. Herein, Au 8 Si dodecahedrons with local five-fold symmetry are revealed as building blocks in Au-Si metallic glass, and the interconnection modes of Au 8 Si dodecahedrons determine the medium-range order. With dimensionality reduction, the surface ordering is attributed to the motif transformation of Au 8 Si dodecahedrons into planar Au 5 Si pyramids with five-fold symmetry, and thus the self-assembly of Au 5 Si pyramids leads to the formation of the ordered Au 2 Si monolayer with the lowest energy. Furthermore, the structural similarity analysis is performed to unveil the physical origin of structural characteristics in different dimensions. The amorphism of Au-Si is due to the smooth energy landscape around the global minimum, while the ordered surface structure occurs due to the steep energy landscape.
@article{arxiv.2205.07032,
title = {Five-fold Symmetry in Au-Si Metallic Glass},
author = {Chang-Chun He and Shao-Gang Xu and Shao-Bin Qiu and Chao He and Yu-Jun Zhao and Xiao-Bao Yang and Hu Xu},
journal= {arXiv preprint arXiv:2205.07032},
year = {2022}
}