Direct observation of atomic-level fractal structure in a metallic glass membrane

• 作者: Hongyu Jiang Jiyu Xu Qinghua Zhang Qian Yu Laiquan Shen Ming Liu Yitao Sun Chengrong Cao Dong Su Haiyang Bai Sheng Meng Baoan Sun Lin Gu Weihua Wang
• 来源期刊: 科学通报（英文版）
• 年，卷（期）: 2021,（13）
• 所属期刊栏目: ARTICLES
• 页码范围: 1312-1318
• 页数: 7页
• 语种: 英文

摘要

Determination and conceptualization of atomic structures of metallic glasses or amorphous alloys remain a grand challenge.Structural models proposed for bulk metallic glasses are still controversial owing to experimental difficulties in directly imaging the atom positions in three-dimensional structures.With the advanced atomic-resolution imaging,here we directly observed the atomic arrangements in atomi-cally thin metallic glassy membranes obtained by vapor deposition.The atomic packing in the amorphous membrane is shown to have a fractal characteristic,with the fractal dimension depending on the atomic density.Locally,the atomic configuration for the metallic glass membrane is composed of many types of polygons with the bonding angles concentrated on 45°-55°.The fractal atomic structure is consistent with the analysis by the percolation theory,and may account for the enhanced relaxation dynamics and the easiness of glass transition as reported for the thin metallic glassy films or glassy surface.