Nonmagnetic doping induced quantum anomalous Hall effect in topological insulators

Quantum anomalous Hall effect (QAHE) has been experimentally observed in magnetically doped topological insulators. However, ultralow temperatures (usually below 300 mK), which are mainly attributed to inhomogeneous magnetic doping, become a daunting challenge for potential applications. Here, a nonmagnetic-doping strategy is proposed to produce ferromagnetism and realize QAHE in topological insulators. We numerically demonstrate that magnetic moments can be induced by nonmagnetic nitrogen or carbon substitution in Bi2Se3, Bi2Te3, and Sb2Te3, while only nitrogen-doped Sb2Te3 system can exhibit long-range ferromagnetism and preserve large bulk band gaps. We further show that its corresponding thin film can harbor QAHE at temperatures of 17-29 Kelvin, which is two orders of magnitude higher than typical realized temperatures in similar systems. Our proposed nonmagnetic doping scheme may shed light on experimental realization of high-temperature QAHE in topological insulators.