二维铁磁材料对拓扑绝缘体电子结构的调控效应研究

近年来，各种有范德瓦尔斯型层状结构的二维铁磁材料不断涌现，在各种磁性异质结中展现了它们对低维量子材料电子结构强大的调控能力。这些材料的出现为高性能非易失性二维材料器件的设计和制造提供了全新的思路。然而，目前二维材料磁性异质结的制造大多仍依赖于机械剥离方法，其随机性大、产率低，难以推广到大规模应用中。针对该领域当前的机遇与挑战，本项目计划利用分子束外延生长方法制备二维铁磁材料与拓扑绝缘体的异质结，并利用超高真空低温/变温扫描隧道显微镜技术对拓扑绝缘体电子结构受到的调控效应进行精确的原位表征。同时，作为对于二维铁磁材料调控能力的验证，我们将结合电输运实验，进一步寻求通过异质结的构建来实现不依赖掺杂的本征量子反常霍尔效应的技术途径。本项目将开辟利用原位生长方法制备二维铁磁材料异质结的新道路，同时以原子级精确度厘清此类异质结中的调控机理，为推动基于二维材料的磁性调控技术的发展做出贡献。

The recently emerging two-dimensional ferromagnetic materials (2DFM) with van der Waals layered structures have shown their powerful tuning effect to the electronic structures of low-dimensional quantum materials. The appearance of these materials provides novel routes for the design and fabrication of high-performance non-volatile 2D-material devices. However, the construction of 2DFM heterostructures is still largely relying on mechanical exfoliation methods. As these methods are highly random and extremely slow, it is difficult to utilize them in large-scale applications. Based on the opportunities and challenges in this field, in this project, we plan to grow the 2DFM/TI heterostructures with molecular beam epitaxy method, and precisely characterize the tuning effect to the electronic structure of TI by in situ low/variable-temperature scanning tunneling microscopy. Besides, as a proof to the tuning effect of 2DFM, we will also work on pursuing the route towards intrinsic quantum anomalous Hall effect, which does not require any doping, by integrating electrical transport measurements into our studies. This project will open a new pathway of fabricating 2DFM heterostructures by in situ growth methods, and reveal the mechanism of tuning effect in these heterostructures in atomic precision, thereby contribute to the development of magnetic tuning technologies based on 2D materials.