By combining first-principles calculations and symmetry arguments, we propose that the half-metallic phase of K 2 Cr 8 O 16 presents ferromagnetic Weyl fermions. In particular, K 2 Cr 8 O 16 possesses two pairs of Weyl nodes, which originate from two groups of nodal lines connected by the mirror reflection symmetry. We show that the non-trivial topological properties of K 2 Cr 8 O 16 come from the partially occupied t 2g states of Cr, and we also demonstrate that such exotic topological feature is robust. The topological surface states and corresponding Fermi arcs are revealed. As K 2 Cr 8 O 16 is a realistic and widely studied material, our results suggest that K 2 Cr 8 O 16 is an ideal candidate for studying ferromagnetic Weyl fermions. In addition, K 2 Cr 8 O 16 possesses several interesting phenomena...

中文翻译：

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K 2 Cr 8 O 16铁磁性高温相中的Weyl费米子

通过结合第一性原理计算和对称性论证，我们提出K 2 Cr 8 O 16的半金属相具有铁磁Weyl费米子。特别地，K 2 Cr 8 O 16具有两对Weyl节点，它们源自通过镜面反射对称性连接的两组节点线。我们表明K 2 Cr 8 O 16的非平凡的拓扑特性来自Cr的部分占据的t 2g态，并且我们还证明了这种奇异的拓扑特性是可靠的。显示了拓扑表面状态和相应的费米弧。由于K 2 Cr 8 O 16是一种现实而广泛研究的材料，因此我们的结果表明，K 2 Cr 8 O 16是研究铁磁Weyl费米子的理想选择。此外，K 2 Cr 8 O 16具有几种有趣的现象...