# Nonmagnetic-Doping Induced Quantum Anomalous Hall Effect in Topological Insulators

## TL;DR

This paper proposes a nonmagnetic doping method using nitrogen to induce ferromagnetism in topological insulators, enabling the quantum anomalous Hall effect at significantly higher temperatures than previous methods.

## Contribution

It introduces a novel nonmagnetic doping strategy with nitrogen that achieves high-temperature QAHE in topological insulators, overcoming limitations of magnetic doping.

## Key findings

- Nitrogen doping induces ferromagnetism in Sb₂Te₃.
- Only nitrogen-doped Sb₂Te₃ shows long-range ferromagnetism.
- QAHE observed at 17-29 Kelvin, much higher than previous systems.

## 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 \textit{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 Bi$_2$Se$_3$, Bi$_2$Te$_3$, and Sb$_2$Te$_3$, but only nitrogen-doped Sb$_2$Te$_3$ 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 \textit{nonmagnetic} doping scheme may shed new light in experimental realization of high-temperature QAHE in topological insulators.