Spectroscopic evidence of flat bands in breathing kagome semiconductor Nb3I8
Spectroscopic evidence of flat bands in breathing kagome semiconductor Nb3I8
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DOI：
10.1038/s43246-022-00318-3
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发表时间：
2022-03
影响因子：
7.8
通讯作者：
Sabin Regmi;Tharindu Fernando;Yuzhou Zhao;Anup Pradhan Sakhya;Gyanendra Dhakal;Iftakhar Bin Elius;
中科院分区：
文献类型：
--
作者：
Sabin Regmi;Tharindu Fernando;Yuzhou Zhao;Anup Pradhan Sakhya;Gyanendra Dhakal;Iftakhar Bin Elius;
Kagome 材料已成为研究几何、拓扑、相关性和磁性之间相互作用的坚实基础。最近，卤化铌半导体 Nb3X8(X= Cl, Br, I) 被预测为二维磁体，这些材料也因其呼吸戈薇几何形状而令人感兴趣。然而，这些有前途的材料的实验电子结构研究仍然缺乏。在这里，我们报告了呼吸戈薇半导体 Nb3I8 中约 500 meV 结合能的平坦且弱色散带的光谱证据，这得到了我们的第一性原理计算的充分支持。这些能带源自铌原子的呼吸戈薇晶格，具有铌轨道特征。人们发现它们对入射光子束的偏振敏感。我们的研究深入了解了可剥离戈薇半导体中的电子结构和平带拓扑，从而为理解二维材料中几何和电子相关性的相互作用提供了一个重要的平台。
Kagome materials have become solid grounds to study the interplay among geometry, topology, correlation, and magnetism. Recently, niobium halide semiconductors Nb3X8(X= Cl, Br, I) have been predicted to be two-dimensional magnets and these materials are also interesting for their breathing kagome geometry. However, experimental electronic structure studies of these promising materials are still lacking. Here, we report the spectroscopic evidence of flat and weakly dispersing bands in breathing-kagome semiconductor Nb3I8around 500 meV binding energy, which is well supported by our first-principles calculations. These bands originate from the breathing kagome lattice of niobium atoms and have niobiumd-orbital character. They are found to be sensitive to the polarization of the incident photon beam. Our study provides insight into the electronic structure and flat band topology in an exfoliable kagome semiconductor, thereby providing an important platform to understand the interaction of geometry and electron correlations in two-dimensional materials.