Understanding the atomic-scale mechanisms that govern the structure of interfaces is critical across materials systems but particularly so for two-dimensional (2D) moiré materials. Here, we image, atom-by-atom, the thermally induced structural evolution of twisted bilayer transition metal dichalcogenides using in situ transmission electron microscopy. We observe low-temperature, local conversion of moiré superlattice into nanoscale aligned domains. Unexpectedly, this process occurs by nucleating a new grain within one monolayer, whose crystal orientation is templated by the other. The aligned domains grow through collective rotation of moiré supercells and hopping of 5|7 defect pairs at moiré boundaries. This provides mechanistic insight into the atomic-scale interactions controlling moiré structures and illustrates the potential to pattern interfacial structure and properties of 2D materials at the nanoscale.

中文翻译：

---

二维过渡金属二硫化物中莫尔变换的原子对原子成像

了解控制界面结构的原子尺度机制对于材料系统至关重要，对于二维 (2D) 莫尔材料尤其如此。在这里，我们使用原位透射电子显微镜逐个原子地对扭曲双层过渡金属二硫族化物的热诱导结构演化进行成像。我们观察到莫尔超晶格在低温下局部转变为纳米级排列的域。出乎意料的是，这一过程是通过在一个单层内成核新晶粒而发生的，该晶粒的晶体取向以另一个单层为模板。对齐的域通过莫尔超晶胞的集体旋转和莫尔边界处 5|7 个缺陷对的跳跃而增长。这提供了对控制莫尔结构的原子尺度相互作用的机制洞察，并说明了在纳米尺度上对二维材料的界面结构和特性进行图案化的潜力。