韩国首尔国立大学Yoo, Hyobin团队近日研究了莫尔-莫尔晶格中的非常规域镶嵌。这一研究成果发表在2025年5月14日出版的《自然》杂志上。

在周期性原子晶格上施加不可通约的周期性会导致由拓扑缺陷约束的局部周期性结构组成的复杂结构相。扭曲三层石墨烯（TTG）是研究不同原子周期性之间相互作用的理想材料平台，可以通过层之间的扭曲角度来调节，从而产生莫尔晶格的莫尔。TTG中两个界面之间的层间和层内相互作用将这种莫尔晶格转化为一个复杂的域结构网络，其扭曲角度很小，可以容纳奇特的电子行为。 

研究组报告了原子尺度晶格重建的TTG的完整结构相图。使用透射电子显微镜（TEM）结合新的原子间势模拟，他们展示了几个大尺度的莫尔晶格，包括三角形、kagome和角共享的六边形畴图案。每个域都由域壁晶格的二维网络界定。在小扭转角的限制下，两种相互竞争的结构阶数——菱面体和伯纳尔堆叠——具有轻微的能量差异，会导致具有自发对称破缺（SSB）和向列不稳定性的非常规晶格重建，突显了整个范德华层中长程层间相互作用的重要性。不同域的不同镶嵌，其拓扑网络可以通过调整扭曲角度来调整，这使TTG成为探索新兴量子特性和可控非平凡晶格之间相互作用的平台。

附：英文原文

Title: Unconventional domain tessellations in moiré-of-moiré lattices

Author: Park, Daesung, Park, Changwon, Yananose, Kunihiro, Ko, Eunjung, Kim, Byunghyun, Engelke, Rebecca, Zhang, Xi, Davydov, Konstantin, Green, Matthew, Kim, Hyun-Mi, Park, Sang Hwa, Lee, Jae Heon, Kim, Seul-Gi, Kim, Hyeongkeun, Watanabe, Kenji, Taniguchi, Takashi, Yang, Sang Mo, Wang, Ke, Kim, Philip, Son, Young-Woo, Yoo, Hyobin

Issue&Volume: 2025-05-14

Abstract: Imposing incommensurable periodicity on the periodic atomic lattice can lead to complex structural phases consisting of locally periodic structure bounded by topological defects1,2,3,4,5,6,7,8. Twisted trilayer graphene (TTG) is an ideal material platform to study the interplay between different atomic periodicities, which can be tuned by twist angles between the layers, leading to moiré-of-moiré lattices9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26. Interlayer and intralayer interactions between two interfaces in TTG transform this moiré-of-moiré lattice into an intricate network of domain structures at small twist angles, which can harbour exotic electronic behaviours9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26. Here we report a complete structural phase diagram of TTG with atomic-scale lattice reconstruction. Using transmission electron microscopy (TEM) combined with a new interatomic potential simulation27,28, we show several large-scale moiré lattices, including triangular, kagome and a corner-shared hexagram-shaped domain pattern. Each domain is bounded by a 2D network of domain-wall lattices. In the limit of small twist angles, two competing structural orders—rhombohedral and Bernal stackings—with a slight energy difference cause unconventional lattice reconstruction with spontaneous symmetry breaking (SSB) and nematic instability, highlighting the importance of long-range interlayer interactions across entire van der Waals layers. The diverse tessellation of distinct domains, whose topological network can be tuned by the adjustment of the twist angles, establishes TTG as a platform for exploring the interplay between emerging quantum properties and controllable nontrivial lattices.

DOI: 10.1038/s41586-025-08932-0

Source: https://www.nature.com/articles/s41586-025-08932-0