Bi₂Te₃-intercalated MnBi₂Te₄: ideal candidate to explore intrinsic Chern insulator and high-temperature quantum anomalous Hall effect

Abstract

The recently discovered magnetic topological insulator of MnBi2Te4 (MBT), has been demonstrated to realize the quantum anomalous Hall (QAH) effect, while the naturally antiferromagnetic (AFM) interlayer coupling in MBT results in that the QAH effect can only be realized in odd-layered systems and at low temperature. Using first-principles calculations, we find that intercalating Bi2Te3 (BT) layers into MBT by forming MBT/(BT) n /MBT (n = 1–6) heterostructures can induce magnetic phase transition from AFM to ferromagnetic (FM) interlayer coupling when n⩾ 3. Specifically, MBT/(BT)3/MBT and MBT/(BT)4/MBT respectively host Curie temperatures T c of 14 K and 11 K, which fits well the experimentally measured T c of 12 K. Detailed band structure calculations and topological identification show that the QAH phases are well preserved for all FM heterostructures. And the topological mechanism of MBT/(BT) n /MBT as a function of n is revealed by employing continuum model analysis. Most importantly, the FM MBT/(BT)4/MBT has already been experimentally fabricated. Thus, our work provides a practical guideline to explore high-temperature QAH effect in MBT family of materials.