High Chern number quantum anomalous Hall effect in monolayer Co3X3SSe (X = Sn, Pb) kagomes

The high Chern number quantum anomalous Hall effect can offer an ideal platform to develop exotic quantum materials with a dissipationless chiral edge. The investigation of kagome monolayer Co3X3SSe (X = Sn, Pb) materials enables a comprehensive exploration of their structural, magnetoelectric, and topological characteristics through first-principles calculations. The monolayers Co3Sn3SSe and Co3Pb3SSe are classified as kagome ferromagnets, and they exhibit stable perpendicular magnetic anisotropy energy. These materials can achieve the intrinsic high Chern number quantum anomalous Hall effect with C = -3. The band gaps of Co3Sn3SSe and Co3Pb3SSe are 46 and 59 meV, respectively, which are larger than the thermal energy at room-temperature scale. Additionally, our findings demonstrate that both the band gap and magnetic anisotropy energy of the monolayers Co3Sn3SSe and Co3Pb3SSe are sensitive to applied strain. This research presents intriguing and alternative possibilities for advancing intrinsic high Chern number quantum anomalous Hall devices.