Template-directed assembly has been shown to yield a broad diversity of highly ordered mesostructures^1,2, which in a few cases exhibit symmetries not present in the native material^3,4,5. However, this technique has not yet been applied to eutectic materials, which underpin many modern technologies ranging from high-performance turbine blades to solder alloys. Here we use directional solidification of a simple AgCl-KCl lamellar eutectic material within a pillar template to show that interactions of the material with the template lead to the emergence of a set of microstructures that are distinct from the eutectic’s native lamellar structure and the template’s hexagonal lattice structure. By modifying the solidification rate of this material–template system, trefoil, quatrefoil, cinquefoil and hexafoil mesostructures with submicrometre-size features are realized. Phase-field simulations suggest that these mesostructures appear owing to constraints imposed on diffusion by the hexagonally arrayed pillar template. We note that the trefoil and hexafoil patterns resemble Archimedean honeycomb and square–hexagonal–dodecagonal lattices⁶, respectively. We also find that by using monolayer colloidal crystals as templates, a variety of eutectic mesostructures including trefoil and hexafoil are observed, the former resembling the Archimedean kagome lattice. Potential emerging applications for the structures provided by templated eutectics include non-reciprocal metasurfaces⁷, magnetic spin-ice systems^8,9, and micro- and nano-lattices with enhanced mechanical properties^10,11.

模板导向装配已被证明可以产生高度有序的介观结构^1,2的广泛多样性，在少数情况下会表现出原生材料中不存在的对称性^3,4,5. 然而，这种技术尚未应用于共晶材料，共晶材料是许多现代技术的基础，从高性能涡轮叶片到焊料合金。在这里，我们使用柱模板内简单的 AgCl-KCl 层状共晶材料的定向凝固来表明材料与模板的相互作用导致出现一组不同于共晶的原生层状结构和模板的六边形结构的微结构。格子结构。通过改变这种材料-模板系统的凝固速率，实现了具有亚微米尺寸特征的三叶形、四叶形、五叶形和六叶形介观结构。相场模拟表明，这些介观结构的出现是由于六边形排列的柱模板对扩散施加的限制。⁶，分别。我们还发现，以单层胶体晶体为模板，观察到包括三叶和六叶在内的多种共晶介观结构，前者类似于阿基米德kagome晶格。由模板共晶提供的结构的潜在新兴应用包括非互易超表面⁷、磁性自旋冰系统^8,9以及具有增强机械性能的微米和纳米晶格^10,11。