First‐Principles Study of Quantum Anomalous Hall Effect in Two‐Dimensional O─As─N

The pursuit of ferromagnetic semiconductors capable of realizing the quantum anomalous hall effect (QAHE) at room temperature holds significant importance for the development and application of spintronic devices. However, current experimental realizations of QAHE in 2D materials are often limited by extremely low T C and minute nontrivial bandgaps. Herein, based on first‐principles calculations, a stable QAHE system that can exist at room temperature is successfully achieved by adsorbing N and O atoms on opposite sides of arsenene. According to the computational results, this novel 2D O─As─N system exhibits ferromagnetic semiconducting behavior with a T C of 350 K and a bandgap of ≈131 meV. Further calculations and analysis of the system's gapless chiral edge states, Chern number (C = 1), and quantized quantum Hall conductivity confirm the topological nontriviality of the bandgap. This work sheds light on the physical mechanisms for developing spintronic devices utilizing room‐temperature ferromagnetic semiconductors and realizing lossless devices through the application of room‐temperature QAHE.