High Chern number quantum anomalous Hall effect tunable by stacking order in van der Waals topological insulators
Wenxuan Zhu, Cheng Song, Hua Bai, Liyang Liao, Feng Pan
Abstract
The discovery of van der Waals (vdW) ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$ provides a platform for investigating the quantum anomalous Hall effect (QAHE), which is a candidate for quantum computation without dissipation. However, because of the topological requirement, the High Chern number QAHE with extended dissipation-free channels is hard to achieve in atomically thin samples, which can take full advantage of two-dimensional (2D) materials. In this work, by first-principles calculations, the variable stacking order (inherent to vdW materials) was proposed as a means of regulating the Chern number of the QAHE in ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$ (MBT). The interlayer stacking order in the 2D limit dominates the orbital hybridization, resulting in a tunable topological property. Furthermore, the High Chern number QAHE with $C=N$ was achieved in ultrathin MBT ($2N$ septuple layers) with alternate stacking orders, which have different topological states. This scenario was extended to the vdW heterostructure of MBT-family materials for achieving a stable, zero-field, High Chern number QAHE. Our work reveals stacking tunable topological properties in vdW magnetic topological insulators and provides an effective means of regulating the QAHE.