拓扑半金属材料的新型器件设计

Topological semimetals, including Weyl semimetals, Dirac semimetals, Node-Line and Hopf-link semimetals, which have unique point or line-like bulk electronic band degeneracies, topological surface states (like Fermi arcs) and exotic quantum chiral anomalies, are the frontier of condensed matter research. Our project will base on four key properties of topological semimetals to explore their novel device applications, including their quantum anomalies, unique bulk electronic structures, low dimensional electronic states different from bulk and size and interface effects of heterojunctions. To make it concrete, we will first design a few novel quantum device based on the bulk electronic properties of topological semimetals. Next we will make use of first principle calculation and analytical models to predict the evolution of band structures of topological semimetal materials under low dimensional limit and their heterojunctions, then explore their device applications. Finally we will deeply study the interface and size effects on the modulation of topological semimetal quantum devices, by device modeling and quantum transport simulations. This project aims to connect the application developments with fundamental research, and will promote the fields of terahertz optoelectronics, low power electronics, spintronics and quantum computing.

拓扑半金属，包括外尔半金属、狄拉克半金属、节线半金属和霍普夫结半金属等，具有独特的点或线的体能带简并结构、拓扑表面态(如费米弧）和量子手性反常等奇妙物性,是凝聚态物理的研究前沿。本项目将紧密围绕拓扑半金属的量子反常效应、独特的体电子能带结构、在低维极限下迥异于三维母体的电子能态和异质结构的尺寸与界面效应四个关键着眼点探索其新型器件应用。具体的讲，我们拟设计一系列基于拓扑半金属体电子性质的新型量子器件；凭借第一性原理计算和解析模型来预测多种拓扑半金属量子材料在低维极限、异质结构下的能带结构变化，并探索其器件应用；利用器件模型和量子输运模拟，深入研究表/界面与尺度等因素对拓扑半金属量子器件的调控。我们的预期项目成果将切实推进前沿基础研究成果的实用开发，并将对太赫兹光电器件、低能耗电子芯片、自旋调控、拓扑量子计算等领域的发展起到良好的推动作用。

拓扑半金属，包括外尔半金属、狄拉克半金属、节线半金属和霍普夫结半金属等，具有独特的点或线的体能带简并结构、拓扑表面态（如费米弧）和量子手性反常等奇妙物性，是凝聚态物理的研究前沿。本项目在具体执行中完成了研究目标并在此基础上拓展了研究内容，具体包括(a) 对拓扑半金属非线性响应的理论和应用研究。(b)动量空间扭结的二维电路实现。(c)二维实现四维受第二陈数保护的纠缠拓扑态。(d)具有非同构对称性的拓扑角态电路。 (e)可迁移网络预测量子多体系统的时序演化。(f)没有任何对称性的实非厄米能谱。(g)光子晶体中非阿贝尔拓扑荷的扭结实现。预期研究成果为5-8篇 SCI 论文，现有8篇已发表并标注，成果符合预期。本项目2020年发表的关于扭结拓扑电路的实现工作（Nature Communications 11，4385，2020，共同通讯作者）获得了物理研究门户网站phys.org和美国科学促进会的EurekAlert！等媒体报道。