美国普林斯顿大学B. Andrei Bernevig团队研究了基于M点扭转的变形材料。相关论文发表在2025年7月9日出版的《自然》杂志上。

当两种单层材料以相对扭曲的方式堆叠时，会出现有效的莫尔平移对称性，导致所得异质结构具有根本不同的性质。因此，莫尔材料最近为探索强相关系统提供了高度可调的平台。然而，之前的研究几乎只关注布里渊区（BZ）Γ或K点附近具有三角形晶格和低能态的单层。

研究组介绍了一类新的莫尔系统，该系统基于具有三角形晶格但在BZ的M点处具有低能态的单层。这些M点莫尔材料具有三重旋转对称性相关的三个时间反转保持谷。他们提出了可剥离1T-SnSe₂和1T-ZrS₂的扭曲双层作为这一新类别的实现。通过广泛的从头计算模拟，确定了产生平坦导带的扭曲角度，提供了精确的连续体模型，分析了它们的拓扑结构和电荷密度，并探索了平台丰富的物理特性。

值得注意的是，M点莫尔哈密顿算子表现出涌现动量空间非对称对称性和kagome平面波晶格结构。据他们所知，这是非磁性系统中晶体空间群投影表示的第一个实验上可行的实现。通过相互作用，这些系统充当了莫特物理学的六味哈伯德模拟器。此外，动量空间非对称平面镜像对称性的存在使得每个谷中的一些M点莫尔哈密顿量准一维，这表明实现卢廷格液体物理学的可能性。

附：英文原文

Title: Moiré materials based on M-point twisting

Author: Clugru, Dumitru, Jiang, Yi, Hu, Haoyu, Pi, Hanqi, Yu, Jiabin, Vergniory, Maia G., Shan, Jie, Felser, Claudia, Schoop, Leslie M., Efetov, Dmitri K., Mak, Kin Fai, Bernevig, B. Andrei

Issue&Volume: 2025-07-09

Abstract: When two monolayer materials are stacked with a relative twist, an effective moiré translation symmetry emerges, leading to fundamentally different properties in the resulting heterostructure. As such, moiré materials have recently provided highly tunable platforms for exploring strongly correlated systems1,2. However, previous studies have focused almost exclusively on monolayers with triangular lattices and low-energy states near the Γ (refs.3,4) or K (refs.5,6,7,8,9) points of the Brillouin zone (BZ). Here we introduce a new class of moiré systems based on monolayers with triangular lattices but low-energy states at the M points of the BZ. These M-point moiré materials feature three time-reversal-preserving valleys related by threefold rotational symmetry. We propose twisted bilayers of exfoliable 1T-SnSe2 and 1T-ZrS2 as realizations of this new class. Using extensive ab initio simulations, we identify twist angles that yield flat conduction bands, provide accurate continuum models, analyse their topology and charge density and explore the platform’s rich physics. Notably, the M-point moiré Hamiltonians exhibit emergent momentum-space non-symmorphic symmetries and a kagome plane-wave lattice structure. This represents, to our knowledge, the first experimentally viable realization of projective representations of crystalline space groups in a non-magnetic system. With interactions, these systems act as six-flavour Hubbard simulators with Mott physics. Moreover, the presence of a momentum-space non-symmorphic in-plane mirror symmetry renders some of the M-point moiré Hamiltonians quasi-one-dimensional in each valley, suggesting the possibility of realizing Luttinger-liquid physics.

DOI: 10.1038/s41586-025-09187-5

Source: https://www.nature.com/articles/s41586-025-09187-5