Tunable Topological Phases in Two-Dimensional Electrides

Electrides have been extensively investigated, whichrevealed manyexotic properties. Here, we suggest two feasible two-dimensional (2D)ferromagnetic electrides HfBa4X8 (X = Cl, Br),whose ground state displays a quantum anomalous Hall effect (QAHE)state with an easy x-axis magnetization. Excess electronsin these materials are confined in the cavity channel created by Ba2+ cations and X- anions and considerablyaffect both the magnetic and topological properties. By rotating themagnetization counterclockwise starting from the x axis, the system can achieve two QAHE states with the opposite Chernnumber and a period change of the band gap, and a 2D Weyl half-semimetalstate will act as a critical point with the magnetization along the y axis. Our findings provide a material family platformfor studying magnetic topological phase transition in electrides,which may exhibit unique applications in spintronic devices.