Epitaxy and structural properties of (V,Bi,Sb) 2Te3 layers exhibiting the quantum anomalous Hall effect

Abstract

(Bi,Sb)${}_{2}$Te${}_{3}$ layers doped with Vanadium are ferromagnetic topological insulators exhibiting the quantum anomalous Hall effect (QAHE) at low temperatures. The Hall resistivity is quantized to h/e${}^{2}$ without an external magnetic field. The authors succeeded in reproducible epitaxial growth of thin layers, with an optimized Sb content in a narrow range around 80% showing the QAHE. Such layers grown on Si or InP substrates and with or without a protecting Te cap show quantization. The QAHE persists independently of the interfaces between cap, layer and substrate, limited crystalline quality, and layer degradation, confirming the robustness of the quantum anomalous Hall effect.