Topological nodal line semimetals with and without spin-orbital coupling
Topological nodal line semimetals with and without spin-orbital coupling
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DOI：
10.1103/physrevb.92.081201
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发表时间：
2015-08-10
影响因子：
3.7
通讯作者：
Fu, Liang
中科院分区：
文献类型：
--
作者：
Fang, Chen;Chen, Yige;Fu, Liang
我们从理论上研究了具有晶体对称性保护的节线的三维拓扑半金属。与具有点节点的TSM相比，例如，Weyl半金属和Dirac半金属，其中导带和价带在离散点处接触，在这些TSM中，两个带在布里渊区的闭合线处交叉。我们提出了两种不同的类的对称性保护的节线的情况下，并在存在的自旋轨道耦合（SOC），分别。在前者中，我们讨论了受反转对称性和时间反转对称性组合保护的节线，然而，与之前研究的相同对称类的节线不同，每条节线都具有Z（2）单极电荷，并且只能被创建（消灭）成对。在第二类中，与SOC，我们表明，非对称性（螺旋轴）保护四带交叉节线的系统具有反转和时间反演对称性。
We theoretically study three-dimensional topological semimetals (TSMs) with nodal lines protected by crystalline symmetries. Compared to TSMs with point nodes, e.g., Weyl semimetals and Dirac semimetals, where the conduction and the valence bands touch at discrete points, in these TSMs the two bands cross at closed lines in the Brillouin zone. We propose two different classes of symmetry protected nodal lines in the absence and in the presence of spin-orbital coupling (SOC), respectively. In the former, we discuss nodal lines that are protected by a combination of inversion symmetry and time-reversal symmetry, yet, unlike previously studied nodal lines in the same symmetry class, each nodal line has a Z(2) monopole charge and can only be created (annihilated) in pairs. In the second class, with SOC, we show that a nonsymmorphic symmetry (screw axis) protects a four-band crossing nodal line in systems having both inversion and time-reversal symmetries.