Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China.
Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305.
Proc Natl Acad Sci U S A. 2017 Oct 3;114(40):10596-10600. doi: 10.1073/pnas.1713261114. Epub 2017 Sep 19.
Recognized as elementary particles in the standard model, Weyl fermions in condensed matter have received growing attention. However, most of the previously reported Weyl semimetals exhibit rather complicated electronic structures that, in turn, may have raised questions regarding the underlying physics. Here, we report promising topological phases that can be realized in specific honeycomb lattices, including ideal Weyl semimetal structures, 3D strong topological insulators, and nodal-line semimetal configurations. In particular, we highlight a semimetal featuring both Weyl nodes and nodal lines. Guided by this model, we showed that GdSI, the long-perceived ideal Weyl semimetal, has two pairs of Weyl nodes residing at the Fermi level and that LuSI (YSI) is a 3D strong topological insulator with the right-handed helical surface states. Our work provides a mechanism to study topological semimetals and proposes a platform for exploring the physics of Weyl semimetals as well as related device designs.
在标准模型中被视为基本粒子的凝聚态 Weyl 费米子受到了越来越多的关注。然而，之前报道的大多数 Weyl 半金属都表现出相当复杂的电子结构，这反过来可能引发了对潜在物理的质疑。在这里，我们报告了在特定的蜂窝状晶格中可以实现的有前途的拓扑相，包括理想的 Weyl 半金属结构、3D 强拓扑绝缘体和节线半金属构型。特别是，我们强调了一种具有 Weyl 节点和节线的半金属。在这个模型的指导下，我们表明 GdSI，长期以来被认为是理想的 Weyl 半金属，在费米能级处有两对 Weyl 节点，而 LuSI（YSI）是具有右手螺旋表面态的 3D 强拓扑绝缘体。我们的工作提供了研究拓扑半金属的机制，并为探索 Weyl 半金属以及相关器件设计的物理提供了一个平台。
