准二维磁性-拓扑-超导界面的构建和物性研究

探寻拓扑非平庸的物质态，是当前凝聚态物理学领域重要的前沿研究方向。将拓扑材料和超导体结合可形成承载Majorana费米子或零能模的拓扑超导体，一种可以用于拓扑量子计算的零能激发态；而拓扑与磁性的结合，可以实现有半量子电导、单向电荷自旋流的量子反常霍尔效应以及轴子绝缘体等。磁性与拓扑、超导的有机结合，可以作为研究多种新奇拓扑物态和效应的平台，用于探索磁性、超导与拓扑之间相互作用以及由此演生的新物理与新应用。本课题将利用极低温强磁场STM、结合MBE生长对该领域展开研究。选取合适的拓扑、超导和二维磁性材料，设计构筑高质量的薄膜或界面，并通过膜厚、掺杂、应力等手段调控其中的磁性、拓扑性或超导性，探索磁性和超导电性单独或协同在拓扑材料中引入所诱导出的新奇物性，着重关注对拓扑超导电性和Majorana费米子的研究，理解其物理内涵及产生机理，为拓扑超导体的实际应用打下基础。

Exploring new topologically nontrivial states is an important research field in condensed matter physics. Topological superconductor, bearing Majorana fermion or Majorana zero mode, can be fabricated by appropriately combining the topological materials and superconductors, which exhibits great application potential in topological quantum computing. While the system combined with topology and magnetism can realize the quantum anomalous Hall effect with half quantum conductance and single channel charge/spin flow, as well as axion insulating state. Organic combination of topology, superconductivity and magnetism provides a good platform to study a variety of novel topological states and effects, and to explore the interaction between superconductivity, magnetism and topology, as well as the resulting new physics and new applications. In this proposal, we will use molecular beam epitaxy (MBE) and scanning tunneling microscopy (STM) equipped with ultralow temperature and high magnetic field to study this field. Suitable topological, superconducting and quasi-two-dimensional magnetic materials will be selected to design and construct high-quality thin films or interfaces, which can be precisely tuned by controlling the film thickness, film stress or carrier doping. By systematic STM measurements, we propose to explore the novel properties induced by the introduction of magnetism and superconductivity in topological materials alone or in coordination, and focuses on the research of topological superconductivity and Majorana fermion, so as to understand their physical picture and mechanism. These studies will lay a foundation for the practical application of topological superconductor.