多层硅烯中拓扑平带的研究

拓扑平带是一种有望实现室温零磁场（分数）量子霍尔效应的新拓扑量子态，由于其新奇的物理性质在近些年得到了广泛关注。理论预测，在强自旋轨道耦合的Kagome阻错结构中，电子波函数交叠引起的量子干涉可产生拓扑平带。最近，我们在实验上获得新的突破，首次在多层硅烯中获得了Kagome阻错势场，并观察到其对应的拓扑平带。研究表明这种新奇量子态和多层硅烯的层间耦合作用有直接关系。在本项目中，我们将主要通过探索和调控多层硅烯中拓扑平带的量子态特征开展研究工作。在充分探索多层硅烯材料制备和精确控制层间耦合的基础上，再结合各种超高真空原位分析手段对所产生的Kagome阻错势场进行深入的分析和研究，探究其产生的拓扑平带的物理本质。利用掺杂元素与吸附原子/分子发展出多种平带非平庸拓扑性质的调控手段。我们期望通过本项目为了解和调控拓扑平带量子特性奠定实验基础，并为在二维体系中实现拓扑电子平带提供可行的技术路线。

Topological flat band is a new topological state, and is expected to achieve room-temperature (fractional) quantum Hall effect without magnetic field. In theory, completely destructive quantum interference occurs if fermions or bosons are confined in a frustrated Kagome lattice with only nearest-neighbor (NN) hopping. Consequently, the dispersion relation of the trapped particles exhibits a completely flat characteristic, that is, the energy is dispersionless in momentum space. Recently, we have made a breakthrough, for the first time, on obtaining electronic flat band in multilayer silicene by generating a Kagome potential field. This quantum state is predominated by interlayer interaction, which was verified by scanning tunneling microscopy. In this project, we will mainly focus on exploration and modulation of topological flat band in multilayer silicene, by in-situ modulation of interlayer rotation and the Kagome potential field in ultra-high vacuum. The characteristics of flat band will be further studied and tuned by doping elements and adsorbed atoms/molecules. Through this project, we expect to lay the experimental foundation for understanding and controlling the properties of topological flat band in multilayer silicene, and to provide a feasible technical route for develop topological flat band in two-dimensional systems.