Nonmagnetic-Doping Induced Quantum Anomalous Hall Effect in Topological Insulators
Abstract
Quantum anomalous Hall effect (QAHE) has been experimentally observed in magnetically doped topological insulators. However, ultra-low temperature (usually below 300 mK), which is mainly attributed to inhomogeneous magnetic doping, becomes a daunting challenge for potential applications. Here, a nonmagnetic-doping strategy is proposed to produce ferromagnetism and realize QAHE in topological insulators. We numerically demonstrated that magnetic moments can be induced by nitrogen or carbon substitution in Bi2Se3, Bi2Te3, and Sb2Te3, but only nitrogen-doped Sb2Te3 exhibits long-range ferromagnetism and preserve large bulk band gap. 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 the typical temperatures in similar systems. Our proposed nonmagnetic doping scheme may shed new light in experimental realization of high-temperature QAHE in topological insulators.
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