Mahmud Md Tareq, Zhai Dawei, Sandler Nancy
Physics and Astronomy Department and Nanoscale and Quantum Phenomena Institute, Ohio University, Athens, Ohio 45701-2979, United States.
Department of Physics, The University of Hong Kong, Hong Kong, China.
Nano Lett. 2023 Aug 23;23(16):7725-7732. doi: 10.1021/acs.nanolett.3c02513. Epub 2023 Aug 14.
The discovery of correlated phases in twisted moiré superlattices accelerated the search for low-dimensional materials with exotic properties. A promising approach uses engineered substrates to strain the material. However, designing substrates for tailored properties is hindered by the incomplete understanding of the relationship between the substrate's shapes and the electronic properties of the deposited materials. By analyzing effective models of graphene under periodic deformations with generic crystalline profiles, we identify strong symmetry breaking as the critical substrate geometric feature for emerging energy gaps and quasi-flat bands. We find continuous strain profiles producing connected pseudomagnetic field landscapes are important for band topology. We show that the resultant electronic and topological properties from a substrate can be controlled with circularly polarized light, which also offers unique signatures for identifying the band topology imprinted by strain. Our results can guide experiments on strain engineering for exploring interesting transport and topological phenomena.
扭曲莫尔超晶格中相关相的发现加速了对具有奇异特性的低维材料的探索。一种很有前景的方法是使用工程衬底对材料施加应变。然而，由于对衬底形状与沉积材料电子特性之间关系的理解不完整，为定制特性设计衬底受到了阻碍。通过分析具有一般晶体轮廓的周期性变形下石墨烯的有效模型，我们确定强对称性破缺是出现能隙和准平带的关键衬底几何特征。我们发现产生相连的赝磁场景观的连续应变轮廓对能带拓扑很重要。我们表明，衬底产生的电子和拓扑特性可以用圆偏振光来控制，这也为识别由应变印记的能带拓扑提供了独特的特征。我们的结果可以指导应变工程实验，以探索有趣的输运和拓扑现象。
