近日，法国巴黎萨克雷大学的A. Plati&G. Foffi及其研究小组取得一项新进展。经过不懈努力，他们发现振动颗粒物质中的准晶体序。相关研究成果已于2024年1月19日在国际知名学术期刊《自然—物理学》上发表。

该研究团队首次在毫米尺度上观察到了准晶体自组装的现象。这一实验在一个完全无热的系统中进行，其中宏观球形颗粒在衬底上振动。从类似液体的无序相开始，颗粒开始局部排列成三种类型的正方形和三角形瓦片，最终形成一条直线，构成了一个八重对称的准晶体。这种准晶体在模拟中已经被预测到，但尚未在非原子系统中被实验观察到。这些结果不仅证明了准晶体自发组装的另一种途径，而且对于平衡和非平衡统计物理之间的联系具有重要意义。

据悉，准晶体是一种具有晶体学性质的非周期结构，其特性与单个晶胞的晶体学性质不相符。四十多年前，在一种金属合金中首次发现了准晶体，这一发现引发了对晶体结构定义的全面重新思考。随后，在不同的微观系统中，人们在更大的长度尺度上也观察到了准晶体结构，其中基本构建块的尺寸范围涵盖了从纳米到微米的范围。

附：英文原文

Title: Quasi-crystalline order in vibrating granular matter

Author: Plati, A., Maire, R., Fayen, E., Boulogne, F., Restagno, F., Smallenburg, F., Foffi, G.

Issue&Volume: 2024-01-19

Abstract: Quasi-crystals are aperiodic structures with crystallographic properties that are not compatible with that of a single unit cell. Their discovery in a metallic alloy more than four decades ago has required a full reconsideration of our definition of a crystal structure. Quasi-crystalline structures have also been discovered at much larger length scales in different microscopic systems for which the size of the elementary building blocks ranges from the nanometre to the micrometre scale. Here we report the first experimental observation of spontaneous quasi-crystalline self-assembly at the millimetre scale. This result is obtained in a fully athermal system of macroscopic spherical grains vibrating on a substrate. Starting from a liquid-like disordered phase, the grains begin to locally arrange into three types of square and triangle tile that eventually align, forming an eight-fold symmetric quasi-crystal that has been predicted in simulation but not yet experimentally observed in non-atomic systems. These results not only demonstrate an alternative route for the spontaneous assembly of quasi-crystals but are of fundamental interest for the connection between equilibrium and non-equilibrium statistical physics.

DOI: 10.1038/s41567-023-02364-1

Source: https://www.nature.com/articles/s41567-023-02364-1