论文标题
轨道选择性的狄拉克费米子和沮丧的kagome-lattice金属cosn中极为平坦的乐队
Orbital-selective Dirac fermions and extremely flat bands in frustrated kagome-lattice metal CoSn
论文作者
论文摘要
分层的Kagome-lattice 3D过渡金属正在成为一个令人兴奋的平台，以探索沮丧的晶格几何和量子拓扑。然而，尚未清楚地观察到典型的kagome电子带，其特征在于被相互毁灭的平坦带盖的一组dirac状带，并且轨道物理学的研究甚至不太好的研究。在这里，我们介绍了COSN中具有轨道分化物理学的近距离书本kagome频段，可以通过在Co Kagome晶格中具有单轨道跳跃的最小紧密结合模型来很好地描述。带宽小于0.2 eV的盖帽平板沿整个布里群区域运行，尤其是沿G-M沿平面外轨道的平面带宽小于0.02 eV。在平面外轨道的狄拉克锥体上通过自旋轨道相互作用引起的能量差距远小于面内轨道，这表明dirac fermions的轨道选择性。
Layered kagome-lattice 3d transition metals are emerging as an exciting platform to explore the frustrated lattice geometry and quantum topology. However, the typical kagome electronic bands, characterized by sets of the Dirac-like band capped by a phase-destructive flat band, have not been clearly observed, and their orbital physics are even less well investigated. Here, we present close-to-textbook kagome bands with orbital differentiation physics in CoSn, which can be well described by a minimal tight-binding model with single-orbital hopping in Co kagome lattice. The capping flat bands with bandwidth less than 0.2 eV run through the whole Brillouin zone, especially the bandwidth of the flat band of out-of-plane orbitals is less than 0.02 eV along G-M. The energy gap induced by spin-orbit interaction at the Dirac cone of out-of-plane orbitals is much smaller than that of in-plane orbitals, suggesting orbital-selective character of the Dirac fermions.
