Zhang Yichao, Baek Ji-Hwan, Lee Chia-Hao, Jung Yeonjoon, Hong Seong Chul, Nolan Gillian, Watanabe Kenji, Taniguchi Takashi, Lee Gwan-Hyoung, Huang Pinshane Y
Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA.
Department of Materials Science and Engineering, Seoul National University, Seoul 08826, Korea.
Sci Adv. 2024 Mar 29;10(13):eadk1874. doi: 10.1126/sciadv.adk1874. Epub 2024 Mar 27.
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.
理解控制界面结构的原子尺度机制在各种材料系统中都至关重要，对于二维（2D）莫尔材料而言尤其如此。在这里，我们使用原位透射电子显微镜逐原子成像扭曲双层过渡金属二硫属化物的热致结构演变。我们观察到莫尔超晶格在低温下局部转变为纳米级取向排列的畴。出乎意料的是，这个过程是通过在一个单分子层内形成一个新晶粒而发生的，其晶体取向由另一个单分子层决定。取向排列的畴通过莫尔超胞的集体旋转以及莫尔边界处5|7缺陷对的跳跃而生长。这为控制莫尔结构的原子尺度相互作用提供了机理见解，并说明了在纳米尺度上对二维材料的界面结构和性质进行图案化的潜力。
