Lu Yue-Hui, Wang Bao-Zong, Liu Xiong-Jun
International Center for Quantum Materials and School of Physics, Peking University, Beijing 100871, China; Collaborative Innovation Center of Quantum Matter, Beijing 100871, China.
Shanghai Branch, National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Shanghai 201315, China; International Center for Quantum Materials and School of Physics, Peking University, Beijing 100871, China.
Sci Bull (Beijing). 2020 Dec 30;65(24):2080-2085. doi: 10.1016/j.scib.2020.09.036. Epub 2020 Oct 1.
There is an immense effort in search for various types of Weyl semimetals, of which the most fundamental phase consists of the minimal number of i.e. two Weyl points, but is hard to engineer in solids. Here we demonstrate how such fundamental Weyl semimetal can be realized in a maneuverable optical Raman lattice, with which the three-dimensional (3D) spin-orbit (SO) coupling is synthesised for ultracold atoms. In addition, a new novel Weyl phase with coexisting Weyl nodal points and nodal ring is also predicted here, and is shown to be protected by nontrivial linking numbers. We further propose feasible techniques to precisely resolve 3D Weyl band topology through 2D equilibrium and dynamical measurements. This work leads to the first realization of the most fundamental Weyl semimetal band and the 3D SO coupling for ultracold quantum gases, which are respectively the significant issues in the condensed matter and ultracold atom physics.
人们正在付出巨大努力寻找各种类型的外尔半金属，其中最基本的相由最少数量（即两个）的外尔点组成，但在固体中很难实现。在此，我们展示了如何在一个可操控的光学拉曼晶格中实现这种基本的外尔半金属，利用该晶格为超冷原子合成三维（3D）自旋轨道（SO）耦合。此外，本文还预测了一种同时存在外尔节点和节点环的新型外尔相，并表明其受非平凡环绕数保护。我们进一步提出了可行的技术，通过二维平衡和动力学测量精确解析3D外尔能带拓扑结构。这项工作首次实现了最基本的外尔半金属能带以及超冷量子气体的3D SO耦合，这分别是凝聚态物理和超冷原子物理中的重要问题。
