Pursuing the high-temperature quantum anomalous Hall effect in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>MnBi</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>Te</mml:mi><mml:mn>4</mml:mn></mml:msub><mml:mo>/</mml:mo><mml:msub><mml:mi>Sb</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>Te</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math> heterostructures
Shifei Qi, Ruiling Gao, Maozhi Chang, Yulei Han, Zhenhua Qiao
Abstract
Quantum anomalous Hall effect (QAHE) has been experimentally realized in magnetically doped topological insulators or intrinsic magnetic topological insulator ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$ by applying an external magnetic field. However, either the low observation temperature or the unexpected external magnetic field (tuning all ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$ layers to be ferromagnetic) still hinders further application of QAHE. Here, we theoretically demonstrate that proper stacking of ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$ and ${\mathrm{Sb}}_{2}{\mathrm{Te}}_{3}$ layers is able to produce intrinsically ferromagnetic van der Waals heterostructures to realize the high-temperature QAHE. We find that interlayer ferromagnetic transition can happen at ${T}_{C}=42\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ when a five-quintuple-layer ${\mathrm{Sb}}_{2}{\mathrm{Te}}_{3}$ topological insulator is inserted into two septuple-layer ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$ with interlayer antiferromagnetic coupling. Band structure and topological property calculations show that ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}/{\mathrm{Sb}}_{2}{\mathrm{Te}}_{3}/{\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$ heterostructure exhibits a topologically nontrivial band gap around 26 meV, that hosts a QAHE with a Chern number of $\mathcal{C}=1$. In addition, our proposed materials system should be considered as an ideal platform to explore high-temperature QAHE due to the fact of natural charge compensation, originating from the intrinsic $n$-type defects in ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$ and $p$-type defects in ${\mathrm{Sb}}_{2}{\mathrm{Te}}_{3}$.