论文标题
在所有磁性空间组中以其淋巴结结构为特征的三个淋巴结点
Triple nodal points characterized by their nodal-line structure in all magnetic space groups
论文作者
论文摘要
我们分析了晶体固体能带中的三重变性淋巴结点[或短点（TPS）。具体而言，我们专注于无自旋的带结构，即当自旋轨道耦合忽略不计时，并考虑通过根据1D和2D不可降低的小型组合的1D和2D不可降低的分解（ICR）的三个频段的交叉来考虑沿着高对称线形成的TPS。结果是根据TP和附近的淋巴线结构的几种特征，将这种TPS的完整分类（包括非晶状体形状）分类。我们表明，目前研究的TPS的分类被13个磁性点基（MPG）耗尽，这些磁点基（MPG）可以作为高对称线的小共同组，并支持1D和2D无旋转ICR。对于确定的10个MPG，TP特征是唯一确定的，没有更多信息。相比之下，对于包含六倍旋转对称性的3个MPG，可能两种类型的TPS，具体取决于交叉ICR的选择。用混凝土材料候选者的第一原理计算说明了13个MPG中每一个的分类结果。
We analyze triply degenerate nodal points [or triple points (TPs) for short] in energy bands of crystalline solids. Specifically, we focus on spinless band structures, i.e., when spin-orbit coupling is negligible, and consider TPs formed along high-symmetry lines in the momentum space by a crossing of three bands transforming according to a 1D and a 2D irreducible corepresentation (ICR) of the little co-group. The result is a complete classification of such TPs in all magnetic space groups, including the non-symmorphic ones, according to several characteristics of the nodal-line structure at and near the TP. We show that the classification of the presently studied TPs is exhausted by 13 magnetic point groups (MPGs) that can arise as the little co-group of a high-symmetry line and which support both 1D and 2D spinless ICRs. For 10 of the identified MPGs, the TP characteristics are uniquely determined without further information; in contrast, for the 3 MPGs containing sixfold rotational symmetry, two types of TPs are possible, depending on the choice of the crossing ICRs. The classification result for each of the 13 MPGs is illustrated with first-principles calculations of a concrete material candidate.
