Quantum anomalous Hall (QAH) effect in magnetic topological insulators is driven by the combination of spontaneous magnetic moments and spin-orbit coupling. Its recent experimental discovery raises the question if higher plateaus can also be realized. Here we present a general theory for QAH effect with higher Chern numbers, and show by first-principles calculations that thin film magnetic topological insulator of Cr-doped Bi2(Se,Te)3 is a candidate for the C=2 QAH insulator. Remarkably, whereas higher magnetic field leads to lower Hall conductance plateaus in the integer quantum Hall effect, higher magnetic moment leads to higher Hall conductance plateaus in the QAH effect.
@article{arxiv.1305.7500,
title = {Quantum Anomalous Hall Effect with Higher Plateaus},
author = {Jing Wang and Biao Lian and Haijun Zhang and Yong Xu and Shou-Cheng Zhang},
journal= {arXiv preprint arXiv:1305.7500},
year = {2013}
}