Doping-induced magnetic and topological transitions in Mn₂X₂Te₅ (X = Bi, Sb) bilayers

We investigate the magnetic and topological properties of Mn₂X₂Te₅ (X = Bi, Sb) using first-principles calculations. We find that both Mn₂Bi₂Te₅ and Mn₂Sb₂Te₅ bilayers exhibit A-type antiferromagnetic order, which can be understood based on the Goodenough–Kanamori–Anderson rules. We further find that an appropriate hole doping can induce a transition from the A-type antiferromagnetic phase to the ferromagnetic phase in these systems, which also experience a transition from a normal insulator to a quantum anomalous Hall phase. Our study thus demonstrates that tunable magnetism and band topology can be achieved in Mn₂X₂Te₅, which may be utilized in the design of new functional electronic devices.