Atomically dispersed tungsten on metal halide monolayer as a ferromagnetic Chern insulator

Abstract

Although the quantum anomalous Hall (QAH) effect has been experimentally observed in several magnetically doped topological insulators, up to now, it only survives at a very low temperature. More suitable candidate QAH insulators that can work at high temperature are much desired. Here, we propose an experimentally feasible way to realize a robust QAH insulator: atomically dispersed transition metals (e.g., W) on a two-dimensional porous metal halide normal insulator (e.g., InI₃), which has been developed as a state-of-the-art chemical technology broadly adopted for homogeneous catalysis. Based on the first-principles calculations, we predict that the atomic W embedded in an InI₃ monolayer forms an intrinsic ferromagnetic QAH insulator, which exhibits robust uniform out-of-plane ferromagnetic order up to ∼160K and a topologically nontrivial band gap of 56 meV with a nonzero Chern number (|C|=2). We also study its magneto-optical Kerr effect and collective plasma excitation modes, which may help for further experimental verifications and measurement of interesting physical features of Dirac-like electronic dispersion. Our results introduce a feasible method to obtain the QAH effect, which may motivate intensive experimental interest in this field.