Dirac and Weyl semimetals

我们建议，以确定新的材料，主机三维狄拉克或外尔点，并通过角度分辨光电子能谱研究其电子结构。我们将重点讨论那些已经通过DFT理论和拓扑不变量或Berry曲率的分析在理论上预测的化合物。将特别关注具有强各向异性狄拉克色散的含Bi准二维系统中外尔态的可能实现。特别是在倾斜反铁磁体中寻找时间反演对称破缺Weyl态，在没有反转中心的化合物中寻找反转对称破缺Weyl态。对候选材料的表面和体电子结构的精细细节的系统研究预计将识别狄拉克和/或外尔半金属态，并为新材料的有针对性的合成提供可能的实用路线。

We propose to identify novel materials which host three-dimensional Dirac or Weyl points and investigate their electronic structure by means of angle-resolved photoemission spectroscopy. We will focus on those compounds which have been predicted theoretically by means of DFT theory and analysis of topological invariants or Berry curvatures. Special attention will be paid to possible realization of the Weyl state in Bi-containing quasi-two dimensional systems with strongly anisotropic Dirac dispersions. In particular, the time-reversal symmetry breaking Weyl state will be searched for in canted antiferromagnets and inversion symmetry breaking Weyl state - in compounds without center of inversion. Systematic studies of fine details of the surface and bulk electronic structures of candidate materials are anticipated to identify the Dirac and/or Weyl semimetallic states and provide possible practical routes for a targeted synthesis of new materials.