Xie Ying-Ming, Gao Xue-Jian, Xu Xiao Yan, Zhang Cheng-Ping, Hu Jin-Xin, Gao Jason Z, Law K T
Department of Physics, Hong Kong University of Science and Technology, Hong Kong, China.
Department of Physics, University of California at San Diego, La Jolla, CA, USA.
Nat Commun. 2021 May 24;12(1):3064. doi: 10.1038/s41467-021-22903-9.
Recently, it was pointed out that all chiral crystals with spin-orbit coupling (SOC) can be Kramers Weyl semimetals (KWSs) which possess Weyl points pinned at time-reversal invariant momenta. In this work, we show that all achiral non-centrosymmetric materials with SOC can be a new class of topological materials, which we term Kramers nodal line metals (KNLMs). In KNLMs, there are doubly degenerate lines, which we call Kramers nodal lines (KNLs), connecting time-reversal invariant momenta. The KNLs create two types of Fermi surfaces, namely, the spindle torus type and the octdong type. Interestingly, all the electrons on octdong Fermi surfaces are described by two-dimensional massless Dirac Hamiltonians. These materials support quantized optical conductance in thin films. We further show that KNLMs can be regarded as parent states of KWSs. Therefore, we conclude that all non-centrosymmetric metals with SOC are topological, as they can be either KWSs or KNLMs.
最近，有人指出，所有具有自旋轨道耦合（SOC）的手性晶体都可以是克莱默斯外尔半金属（KWSs），其外尔点固定在时间反演不变动量处。在这项工作中，我们表明，所有具有SOC的非手性非中心对称材料都可以是一类新的拓扑材料，我们将其称为克莱默斯节线金属（KNLMs）。在KNLMs中，存在连接时间反演不变动量的双重简并线，我们称之为克莱默斯节线（KNLs）。KNLs产生两种类型的费米面，即纺锤环面型和八面体型。有趣的是，八面体费米面上的所有电子都由二维无质量狄拉克哈密顿量描述。这些材料在薄膜中支持量子化光导率。我们进一步表明，KNLMs可以被视为KWSs的母体状态。因此，我们得出结论，所有具有SOC的非中心对称金属都是拓扑的，因为它们可以是KWSs或KNLMs。
