Discovery of a Weyl fermion semimetal and topological Fermi arcs
Discovery of a Weyl fermion semimetal and topological Fermi arcs
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DOI：
10.1126/science.aaa9297
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发表时间：
2015-08-07
期刊：
影响因子：
56.9
通讯作者：
Hasan, M. Zahid
中科院分区：
文献类型：
--
作者：
Xu, Su-Yang;Belopolski, Ilya;Hasan, M. Zahid
外尔半金属是一种新的物质状态，它拥有外尔费米子作为涌现准粒子，并承认一种拓扑分类，以保护体样品边界上的费米弧表面态。这种不寻常的电子结构与粒子物理学有很深的相似之处，并导致了独特的拓扑性质。我们报告的外尔半金属，砷化钽（TaAs）的实验发现。利用光电子能谱，我们直接观察到费米弧的表面上，以及外尔费米子锥和外尔节点的大部分TaAs单晶。我们发现费米弧终止于外尔费米子节点，符合其拓扑性质。我们的工作为物理学和材料科学中外尔费米子的实验研究开辟了新的领域。
A Weyl semimetal is a new state of matter that hosts Weyl fermions as emergent quasiparticles and admits a topological classification that protects Fermi arc surface states on the boundary of a bulk sample. This unusual electronic structure has deep analogies with particle physics and leads to unique topological properties. We report the experimental discovery of a Weyl semimetal, tantalum arsenide (TaAs). Using photoemission spectroscopy, we directly observe Fermi arcs on the surface, as well as the Weyl fermion cones and Weyl nodes in the bulk of TaAs single crystals. We find that Fermi arcs terminate on the Weyl fermion nodes, consistent with their topological character. Our work opens the field for the experimental study of Weyl fermions in physics and materials science.