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arXiv · 2211.08938

Large-Gap Quantum Anomalous Hall Insulators in $A$Ti$X$ Class

Yadong Jiang·Huan Wang·Jing Wang
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Abstract

We theoretically propose that the monolayer $A$Ti$X$ family (KTiSb, KTiBi, RbTiSb, SrTiSn) are potential candidates for large-gap quantum anomalous Hall insulators with high Chern number $\mathcal{C}=2$. Both of the topology and magnetism in these materials are from $3d$-orbitals of Ti. We construct the tight-binding model with symmetry analysis to reveal the origin of topology. Remarkably, quite different from the conventional $s$-$d$ band inversion, here the topological band inversion within $3d$ orbitals is due to the crystal field and electron hopping, while spin-orbit coupling only trivially gaps out the Dirac cone at Fermi level. The general physics from the $3d$ orbitals here applies to a large class of transition metal compounds with the space group $P4/nmm$ or $P$-$42m$ and their subgroups.

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Yadong Jiang, Huan Wang, Jing Wang. 2022-11-16. Large-Gap Quantum Anomalous Hall Insulators in $A$Ti$X$ Class. https://doi.org/10.1103/physrevb.108.165122

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