拓扑半金属量子输运理论

Weyl semimetal is a three-dimensional (3D) topological state of matter, in which the conduction and valence energy bands touch at a finite number of nodes. The nodes always appear in pairs, in each pair the quasiparticles (dubbedWeyl fermions) carry opposite chirality and linear dispersion, much like 3D analogue of graphene. In the past few years, a number of condensed matter systems have been suggested to host Weyl fermions. Most recently, the signatures of Weyl nodes have been observed by angle-resolved photoemission spectroscopy and scanning tunneling microscopy (Strictly speaking, they are Dirac semimetals in which the paired Weyl nodes are degenerate). This project aims to study the quantum transport in topological semimetals, focusing on a variaty of mechnisms that could contribute to the electric conductivity of a topological semimatal, including weak anti-localization, electron-electron interaction, chiral anomaly, Hall effect, anomalous Hall efffect, effects of Fermi arc, and distinction between different impurity types, etc.

拓扑半金属是一种新奇的三维拓扑物质态，其中导带和价带在有限个动量能量点接触在一起。这些点总是成对出现，每一对的准粒子 (被称作魏尔费米子) 携带相反的手征和线性色散关系，非常像石墨烯在三维的对应。最近几年，一系列凝聚态系统被预言其中存在魏尔费米子。最近，角分辨光电子谱和扫描隧道显微镜开始在凝聚态体系探测到魏尔费米子的迹象，激发了一系列在拓扑半金属中的输运实验和理论的研究。本计划书旨在研究拓扑半金属中的量子输运行为，集中研究影响拓扑半金属电导的各种因素，包括弱反局域化，电子相互作用，手征反常，霍尔效应，反常霍尔效应，费米弧的贡献，各种不同类型杂质的区别等。

拓扑半金属是一种新奇的三维拓扑物质态, 其中被预言其中存在魏尔费米子。本计划书旨在研究拓扑半金属中的量子输运行为，集中研究影响拓扑半金属电导的各种因素，包括电子相互作用和各种不同类型杂质散射等。本项目创新性贡献包括发展了拓扑半金属等拓扑物质从弱磁场到极强磁场下的电子输运理论，被实验广泛用于解释各种新奇现象，包括弱反局域化、负磁阻、量子振荡、量子极限等。其中一个重要预言是三维量子霍尔效应的新机制，已被多个实验验证并正面引用，为实现这个已寻找三十年的物相开辟了新路。项目共支持在物理学期刊发表了29篇论文，包括9篇PRL (8篇通讯作者), 2篇Nature, 1篇Nature Physics (通讯作者), 4篇Nature Communications (2篇通讯作者).