Thickness Dependence of the Quantum Anomalous Hall Effect in Magnetic Topological Insulator Films

摘要

The evolution of the quantum anomalous Hall effect with the thickness of Cr-doped (Bi,Sb)(2)Te-3 magnetic topological insulator films is studied, revealing how the effect is caused by the interplay of the surface states, band-bending, and ferromagnetic exchange energy. Homogeneity in ferromagnetism is found to be the key to high-temperature quantum anomalous Hall material.