论文标题
磁性沙漏费用：从详尽的对称条件到高通量材料预测
Magnetic hourglass fermions: from exhaustive symmetry conditions to high-throughput materials predictions
论文作者
论文摘要
许多拓扑带（BC）已被预测有效地利用高对称点的波函数的对称特性。在各种BC中，所谓的沙漏BC（具有低能的激发被称为沙漏费米子）令人着迷，因为即使没有现实计算，也可以在特定的对称条件下保证它们在特定的对称条件下存在。这种新颖的特性对磁性拓扑金属的理论预测独立于计算方法上，它独立于计算方法，仅由晶体和磁性结构的对称性确定，即磁性空间组（MSG）。迄今为止，还没有使用沙漏费物验证的磁性材料。在这里，我们首先列出了允许在1651毫秒和528个具有自旋轨道耦合（SOC）的528个磁性层组（MLG）中的沙漏BC（MLG）中的对称条件：只有331个msg和53 mlgs可以托管Hourglass BCS。在这些结果中，突出显示了必需的沙漏BC，然后将其MSG应用于Magndata磁性材料数据库中的数百种磁性材料，并在LDA+SOC+U验证$ U $值的Hourglass BC的框架中验证Hourglass BC的框架中的第一原理计算。我们采用CSMN $ _2 $ f $ _6 $，最近与扭曲的pyrochlore结构合成，以说明详细的沙漏频带结构，在费米级别上非常清楚，在费米级别上，受到拓扑的表面鼓状（100）的表面表面的表面效果超过一半，并且在一个狭窄的能量范围内（$ $ \ $ 30）出现$ 30 $ 30 $ 30 $ 30 $ 30 $ 30 $ 30 $ 30 $ 30 $ 30电子相关。
Many topological band crossings (BCs) have been predicted efficiently utilizing the symmetry properties of wave-functions at high-symmetry points. Among various BCs, the so-called hourglass BCs (with the low-energy excitations dubbed as hourglass fermions) are fascinating since they can be guaranteed to exist under specific symmetry conditions even without realistic calculations. Such novel property renders the theoretical prediction on magnetic topological metals with hourglass BC (being Weyl point, Dirac point, lying in nodal loop, and so on) independent on the calculation methods and only determined by the symmetry of crystal and magnetic structure, namely, the magnetic space group (MSG). To date, there have no magnetic material verified with hourglass fermions. Here we first list all symmetry conditions that allow hourglass BCs in the 1651 MSGs and 528 magnetic layer groups (MLGs) with spin-orbital coupling (SOC): Only 331 MSGs and 53 MLGs can host hourglass BCs. Among these results, the essential hourglass BCs are highlighted, whose MSGs are then applied to predict hundreds of magnetic materials from the MAGNDATA magnetic materials database and first-principles calculations in the frame of LDA+SOC+U verify the hourglass BCs for different values of $U$. We take CsMn$_2$F$_6$, synthesized recently with a distorted pyrochlore structure to illustrate the hourglass band structure in detail which is very clear around the Fermi level and the topologically protected surface drumhead states of (100) surface are found to spread over more than one half surface Brillouin zone and only appear in a narrow energy window ($\sim 30$ meV), which could induce intriguing stability by prominent electronic correlation.
