Opt Lett. 2023 May 1;48(9):2349-2352. doi: 10.1364/OL.490001.
Dirac-Weyl semimetal is a novel type of topological phase that features the coexistence of Dirac and Weyl points in momentum space. In this study, a photonic Dirac-Weyl semimetal is proposed by introducing screw rotation symmetries into a spatial inversion symmetry-lacking system. A realistic metacrystal structure is designed for experimental consideration. The screw rotation symmetries are crucial for the existence of Dirac points, whose Z topology is revealed by the (010) surface states. Meanwhile, two pairs of ideal Weyl points at the same frequency are protected by D point group symmetries. The Dirac points and Weyl points reside in a clean frequency interval. The proposed photonic Dirac-Weyl semimetal provides a versatile platform for exploring the interaction between Dirac and Weyl semimetals and exploiting possible photonic topological devices.
狄拉克-外尔半金属是一种新型拓扑相，其特征是在动量空间中同时存在狄拉克点和外尔点。本研究通过在缺乏空间反演对称性的系统中引入螺旋旋转对称性，提出了一种光子狄拉克-外尔半金属。为了实验考虑，设计了一个现实的超晶格结构。螺旋旋转对称性对于狄拉克点的存在至关重要，狄拉克点的 Z 拓扑通过（010）表面态揭示。同时，两对位于相同频率的理想外尔点受到 D 点群对称性的保护。狄拉克点和外尔点位于一个干净的频率间隔内。所提出的光子狄拉克-外尔半金属为探索狄拉克和外尔半金属之间的相互作用以及开发可能的光子拓扑器件提供了一个通用平台。
