Duality between atomic configurations and Bloch states in twistronic materials
Duality between atomic configurations and Bloch states in twistronic materials
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DOI：
10.1103/physrevresearch.2.033162
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发表时间：
2020-07-29
影响因子：
4.2
通讯作者：
Kaxiras, Efthimios
中科院分区：
文献类型：
--
作者：
Carr, Stephen;Massatt, Daniel;Kaxiras, Efthimios
堆叠的二维（2D）材料的连续层的相对取向（扭曲）在层间原子注册中产生变化。这些变化通常会形成超晶格，称为莫尔图案，它可以改变电子特性。在这项工作中，我们介绍了一个分类的单粒子电子结构，可以发生在扭曲的堆栈的二维层，通过表征他们作为“莫尔分子”或“莫尔晶体”。“分子产生局部电子态和莫尔平带，而晶体有时是非常规的，并在配置基础上产生电子带。这种分类的基础是层间配置和单层布洛赫动量在莫尔哈密顿之间的对偶性。我们将这种理解应用于非扭曲几何中的局部电子密度图，以产生对扭子性质的直观和定量预测。我们提供了一个概念性的介绍这个框架，通过一个一维模型，然后将其应用到二维扭曲的双层的半金属石墨烯，和二硫化钼，过渡金属二硫族化物家族的半导体的代表性材料。这种对双电子现象的透彻理解对于寻找新的局域莫尔电子材料平台至关重要。
The relative orientation (twist) of successive layers of stacked two-dimensional (2D) materials creates variations in the interlayer atomic registry. The variations often form a superlattice, called a moire pattern, which can alter electronic properties. In this work we introduce a classification of the single-particle electronic structures that can occur in twisted stacks of 2D layers by characterizing them as "moire molecules" or "moire crystals." The molecules generate localized electronic states and moire flat bands, while the crystals are sometimes unconventional and produce electronic banding in the configuration basis. The underpinning of this classification is the duality between interlayer configuration and monolayer Bloch momentum in moire Hamiltonians. We apply this understanding to diagrams of local electron density in untwisted geometries to produce intuitive and quantitative predictions of twistronic properties. We provide a conceptual introduction to this framework through a one-dimensional model, and then apply it to 2D twisted bilayers of the semimetal graphene, and of MoS2, a representative material of the transition metal dichalcogenide family of semiconductors. This level of thorough understanding of twistronic phenomena is vital in the search for new material platforms for localized moire electrons.