无能隙拓扑物态的物理性质研究

Topological matters are among the most important recent developments in condensed matter physics. Topological matters with bulk energy gap have been extensively investigated both theoretically and experimentally, however, gapless topological matters are much less investigated. In this project, we will focus on several central theoretical problems in this promising field, including the bulk physical properties of gapless topological matters; surface physical properties of gapless topological matters; topological dislocations in gapless topological materials; fractionalized gapless topological matters. The ultimate purpose of this project is to systematically understand gapless topological matters.

拓扑物态是近几年来凝聚态物理中重要的新兴方向。具有体态能隙的拓扑物态(例如拓扑绝缘体)的物理性质在理论和实验方面都已经得到广泛研究，然而，无能隙的拓扑物态(Weyl半金属和nodal line半金属等)的实验研究才刚刚起步，相应的理论工作也很缺乏。本课题瞄准这一具有重要发展潜力的方向，集中研究几个重要问题，包括无能隙拓扑物态的体态物理性质； 无能隙拓扑材料的表面态物理性质；无能隙拓扑材料中的拓扑缺陷；分数化的无能隙拓扑物态等。本课题的目的在于系统深入地理解无能隙的拓扑物态。

本项目对以无能隙拓扑态为代表的新型拓扑物态开展了三个方面的研究。 拓扑半金属方面，我们提出了两类新型拓扑半金属(节线链半金属、节线结半金属)的概念，并系统地研究了周期驱动拓扑体系的拓扑不变量；拓扑量子计算方面，我们提出了不依赖于拓扑超导体来实现马约拉纳零模的思路；非厄米物理方面，我们提出了非厄米体系的拓扑能带理论，引进了非厄米趋肤效应、广义布里渊区等概念，为非厄米拓扑物态方向的研究打下基础。我们的多项理论预言被实验证实。本项目执行期间(2017.01-2020.12), 共发表论文16篇，其中包括Physical Review Letters 6篇(均为第一标注), Nature Physics 2篇, Nature Communications 3篇。其中四篇文章SCI引用超过100次(均为第一标注), 最高为313次。