Engineering Quantum Anomalous Hall Effect with a High Chern Number in Nonmagnetic Second‐Order Topological Insulator

Abstract Quantum anomalous Hall effect (QAHE) with a high Chern number hosts multiple dissipationless edge states, which is of significant fundamental and technological importance in low‐dissipation spintronics. Here, in contrast to generally reported QAHE in 2D ferromagnets, the emergence of high‐Chern‐number QAHE in 2D nonmagnets is theoretically demonstrated. Remarkably, tight‐binding model analyses and calculations show that Floquet engineering offers a fertile strategy to achieve the QAHE in 2D nonmagnetic second‐order topological insulators (SOTIs), with the Chern number reaching as much as . Moreover, based on the Chern number, corner states, and edge states analyses, the SMoSiN₂ monolayer is identified as an experimentally feasible candidate of the proposed mechanism of Floquet QAHE, where a topological phase transition from the 2D nonmagnetic SOTI to QAHE emerges. These findings pave a technological avenue to bridge the higher‐order topology and exotic QAH physics with high feasibility of applications in topological spintronics.