拓扑材料体系及其异质结的奇特物性优化与调控

Recent discoveries of different classes of topological materials represent a major revolutionary advance in condensed matter physics. Accompanying the discovery of every new class of topological materials, the next challenge is how to tune and optimize their exotic physical properties for potential technological applications. In this project, we propose to carry out synergistic theoretical and experimental studies surrounding two widely recognized challenging problems of fundamental importance in this field. First, we will exploit compensated n-p codoping as an enabling new approach to realizing the quantum anomalous Hall effect in magnetic topological insulator thin films at the drastically elevated temperature of liquid nitrogen. Secondly, we will introduce proper types of defects at the interfaces of topological insulators and conventional superconductors or into conventional superconducting layers with strong Rashba spin-orbit coupling to achieve chiral topological superconductivity. Furthermore, we will explore the rubustness, tunability, and functional properties of the topological surface states of topological insulators covered with different classes of topologically trivial overlayers (including metal, semimetal, and semiconductor). This project is expected to offer new insights and new materials choices in physical realization and optimization of several central properties of topological states, and will also help to broaden the scope of the technological significance of topological materials.

凝聚态物理领域近年来的一大革命性进展是一系列新型拓扑材料体系的发现。随着每类拓扑材料为科学界所认知，接踵而来的挑战是如何优化与调控其奇特物性，进而展示其应用前景。本项目以实现高温量子反常霍尔效应及实现手性拓扑超导体为两个核心科学目标，拟开展系统深入的理论与实验研究，主要内容侧重: 1）基于电荷补偿型n-p共掺杂的新思路，探讨磁性拓扑绝缘体薄膜体系在液氮温区实现量子反常霍尔效应的可行性；2）在拓扑绝缘体与常规超导体异质结界面或具有强Rashba自旋轨道耦合的二维超导体里引入合适的杂质，以实现手性拓扑超导体；3）以应用为目标，探讨拓扑绝缘体衬底上不同类型的常规材料覆盖层（包括金属、半金属与半导体）对拓扑表面态空间分布的影响与调控，并进而展示拓扑表面态的鲁棒性在表面催化等方面的积极作用。本项目的实施将为优化拓扑态的若干关键物性提供新机遇，并拓展这些新奇物性在未来自旋电子学与能源器件中的应用前景。

近年来，拓扑材料体系的发展有力推动了凝聚态物理领域围绕新奇拓扑量子物态的基础与应用研究。其中尤其突出的是，拓扑与超导的结合被广泛期待为实现高容错率的拓扑量子计算的重要途径之一。本项目以实现高温量子反常霍尔效应及拓扑超导体为两个核心科学目标，开展了系统深入的理论与实验研究，在新型本征拓扑超导体系、新型二维高温超导体系、界面超导增强机制、新型高温量子反常霍尔效应体系、拓扑复合体系的物性调控、新型二维功能材料、低维材料可控生长等方面取得了一系列开创性研究成果，并受到相关领域研究者的高度关注。共发表 SCI 论文 82 篇，其中包含 Physical Review Letters 7 篇、Nature Physics 1 篇、Nature Photonics 1 篇、Nature Communications 4 篇、Science Bulletin 1 篇。培养博士毕业生 11 人、硕士毕业生 8 人、博士后出站 1 人。1 人获得国家优秀青年科学基金。