美国科罗拉多矿业学院Ning Wu团队研究了胶体准结晶的直接观测。2025年3月31日出版的《自然—物理学》杂志发表了该项成果。

准晶首先在合成合金中发现，随后在自然界中发现，它表现出禁止的对称性和长程取向顺序，但缺乏平移周期性。尽管进行了大量的理论和数值研究，但准晶的制造仍然是一个挑战，可用于原位观察其形成的手段有限。因此，关于准晶形成和稳定的详细机制仍然存在问题。在光学显微镜下可观察到，微米级胶体系统几十年来一直被用作原子模型，通过表面改性、溶液组成和施加外部场，其动力学和可调相互作用显著减慢。

研究组表明，通过正交施加的磁场和电场的组合，二维十二角准晶可以由单组分微球可逆地组装而成。改变施加场的幅度和频率不仅决定了最终的结构，而且通过有效的系统温度设定了相变动力学。研究组假设这些准晶在能量上是稳定的，它们的形成是由各向同性双阱对势驱动的，尽管第二个最小值的起源仍然是一个悬而未决的问题。

附：英文原文

Title: Direct observation of colloidal quasicrystallization

Author: Gao, Yan, Sprinkle, Brennan, Marr, David W. M., Wu, Ning

Issue&Volume: 2025-03-31

Abstract: Discovered first in synthetic alloys and subsequently in nature, quasicrystals exhibit forbidden symmetries and long-range orientational order but lack translational periodicity. Despite numerous theoretical and numerical studies, the fabrication of quasicrystals remains a challenge, with limited means available for observing their formation in situ. As a result, questions remain regarding the detailed mechanisms of quasicrystal formation and stabilization. Observable under optical microscopes, micrometre-scale colloidal systems have been used for decades as atomic models with considerably slowed-down dynamics and tuneable interactions through surface modification, solution composition and applied external fields. Here we show that two-dimensional dodecagonal quasicrystals can be reversibly assembled from single-component microspheres using a combination of orthogonally applied magnetic and electric fields. Varying the magnitude and frequency of the applied fields not only determines the resulting structures but also sets the phase transition dynamics via an effective system temperature. We hypothesize that these quasicrystals are energetically stabilized with their formation driven by an isotropic double-well pair potential, although the origin of the second minimum remains an open question.

DOI: 10.1038/s41567-025-02859-z

Source: https://www.nature.com/articles/s41567-025-02859-z