Tunable Chern Number and Sizable Bandgap in Kagome‐Honeycomb‐Triangle Latticed Quantum Anomalous Hall Insulator

Abstract The search of 2D magnetic materials with quantum anomalous Hall (QAH) effect is a fascinating topic in the field of condensed matter physics, which holds great promise for topological quantum computing. This work proposes that Kagome‐Honeycomb‐Triangle lattice Cr 3 O 4 Cl monolayer represents a class of ferromagnetic Weyl half‐metal with high Curie temperature. Upon considering the spin‐orbit coupling (SOC) effect, the Weyl point is broken and a topologically nontrivial gap of 101.96 meV is opened. Under biaxial tensile strain, the Cr 3 O 4 Cl monolayer is transformed from QAH metal to QAH insulator with Chern number C = 1. Remarkably, a Chern number phase transition from C = 1 to C = 3 can be achieved via manipulating the hole concentration of 1.05 holes per unit cell. This work proposes a platform for realizing 2D high Chern number QAH effect for practical applications.