Weyl semimetals are three-dimensional (3D) gapless topological phases with Weyl cones in the bulk band. According to lattice theory, Weyl cones must come in pairs, with the minimum number of cones being two. A semimetal with only two Weyl cones is an ideal Weyl semimetal (IWSM). Here we report the experimental realization of an IWSM band by engineering 3D spin-orbit coupling for ultracold atoms. The topological Weyl points are clearly measured via the virtual slicing imaging technique in equilibrium and are further resolved in the quench dynamics. The realization of an IWSM band opens an avenue to investigate various exotic phenomena that are difficult to access in solids.

Weyl半金属是三维（3D）无间隙拓扑相，在本体带中具有Weyl锥。根据晶格理论，Weyl锥必须成对出现，锥的最小数量为2。只有两个Weyl锥体的半金属是理想的Weyl半金属（IWSM）。在这里，我们报告了通过对超冷原子进行3D自旋轨道耦合工程实现的IWSM波段的实验实现。通过平衡状态下的虚拟切片成像技术可以清楚地测量拓扑Weyl点，并在淬灭动力学中进一步解析。IWSM波段的实现为研究固体中难以接近的各种奇异现象开辟了一条途径。