Baidya Santu, Kang Seungjin, Kim Choong H, Yu Jaejun
Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Korea.
Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea.
Sci Rep. 2019 Sep 24;9(1):13807. doi: 10.1038/s41598-019-50163-7.
Based on first-principles density-functional theory (DFT) calculations, we report that the transition-metal bis-dithiolene, MCS (M = Mn and Fe), complexes can be a two-dimensional (2D) ferromagnetic insulator with nontrivial Chern number. Among various synthetic pathways leading to metal bis-dithiolenes, the simplest choice of ligand, Benzene-hexathiol, connecting metal cations to form a Kagome lattice is studied following the experimental report of time-reversal symmetric isostructural compound NiCS. We show sulfur and carbon-based ligands play the key role in making the complexes topologically nontrivial. An unusual topological quantum phase transition induced by the on-site Coulomb interaction brings a nearly flat band with a nonzero Chern number as the highest occupied band. With this analysis we explain the electronic structure of the class MCS and predict the existence of nearly flat band with nonzero Chern number and it can be a fractional Chern insulator candidate with carrier doping.
基于第一性原理密度泛函理论（DFT）计算，我们报告过渡金属双二硫纶配合物MCS（M = Mn和Fe）可以是具有非平凡陈数的二维（2D）铁磁绝缘体。在导致金属双二硫纶的各种合成途径中，遵循时间反演对称同构化合物NiCS的实验报告，研究了连接金属阳离子以形成 Kagome 晶格的最简单配体苯六硫醇。我们表明硫基和碳基配体在使配合物具有非平凡拓扑结构方面起着关键作用。由在位库仑相互作用引起的不寻常拓扑量子相变带来了一个具有非零陈数的近平坦能带作为最高占据能带。通过这种分析，我们解释了MCS类的电子结构，并预测了具有非零陈数的近平坦能带的存在，并且它可以是具有载流子掺杂的分数陈绝缘体候选物。
