Yalameha Shahram, Nourbakhsh Zahra
Department of Physics, Faculty of Sciences, University of Isfahan, Isfahan, Iran.
J Phys Condens Matter. 2020 Jul 8;32(29):295502. doi: 10.1088/1361-648X/ab80f4.
In recent years, topological semimetals such as Weyl, Dirac, and nodal-line semimetals have been a hot topic in the field of condensed matter physics. Depending on the orientation of band crossing in momentum space, topological semimetals and metals can be identified as type-I or type-II. Here, we report the coexistence of two new types of topological metal phase in the ScM (M = Cu, Ag, Au) intermetallic compounds (IMCs): (1) multi-nodal-lines semimetals (above Fermi energy), (2) critical-type nodal-lines (lower than Fermi energy). The first case has already been investigated. So, in this paper, we focus on the second case. We find that these IMCs can be an existing topological metal lower than Fermi energy, which are characterized with type-I (for ScCu and ScAu) and critical-type (for ScAg) nodal-lines in the bulk and drumhead liked surface states in the absence of the spin-orbit coupling (SOC). It has also been shown that when SOC is included, these compounds are converted into topological metal materials.
近年来，外尔半金属、狄拉克半金属和节线半金属等拓扑半金属一直是凝聚态物理领域的热门话题。根据动量空间中能带交叉的取向，拓扑半金属和金属可分为I型或II型。在此，我们报道了ScM（M = Cu、Ag、Au）金属间化合物（IMC）中两种新型拓扑金属相的共存：（1）多节线半金属（高于费米能），（2）临界型节线（低于费米能）。第一种情况已被研究过。因此，在本文中，我们聚焦于第二种情况。我们发现这些IMC可以是低于费米能的现有拓扑金属，其在无自旋轨道耦合（SOC）时，体相中具有I型（对于ScCu和ScAu）和临界型（对于ScAg）节线以及鼓面状表面态。研究还表明，当考虑SOC时，这些化合物会转变为拓扑金属材料。
