Colloidal quasicrystals assembled under orthogonally applied magnetic and electric fields

Discovered first in synthetic alloys and later in nature, quasicrystals exhibit “forbidden” symmetries and long-range orientational order despite lacking periodicity. Although extensively studied theoretically and numerically, experimentally realizing quasicrystals remains challenging, and few methods allow their formation to be observed in situ. Consequently, the detailed mechanisms governing quasicrystal formation and stabilization remain poorly understood. In this talk, we demonstrate that two-dimensional dodecagonal quasicrystals can be reversibly assembled from single-component microspheres by applying orthogonal magnetic and electric fields. These microspheres represent the largest known colloidal building blocks capable of forming quasicrystals spontaneously. This system enables direct, real-time characterization of heterogeneous and homogeneous nucleation processes during both solid–solid and liquid–solid phase transitions. We hypothesize that the orthogonal fields independently control the magnitude and direction of dipolar attractions and repulsions between particles. Furthermore, electrohydrodynamic interactions give rise to a variety of novel structures—including dodecagonal quasicrystals, square crystals, colloidal rings, and gear-like assemblies. Our approach provides a versatile and accessible method for generating complex, hierarchical structures that are challenging to achieve using a single external field.