Two-dimensional valleytronic semiconductor with spontaneous spin and huge valley polarization in monolayer MnCoO6Bi2

Two-dimensional (2D) valley materials with valley-polarized band structures have received extensive discussions for their potential applications in the emerging valleytronics, while 2D materials with both spontaneous valley polarization and spin polarization are quite rare. Here, we predict a new 2D ferromagnetic semiconductor MnCoO6Bi2 possessing spontaneous valley polarization by first-principles calculations. The results show that MnCoO6Bi2 has large valley polarization strength of 254 meV and ferromagnetic Curie temperature of 214 K, which is sufficient for the observation of anomalous valley Hall effects. In addition, the band structure with valley polarization can be well maintained under external biaxial strains between-6% and 6%. Our findings provide an ideal platform for exploring the valleytronic physics in 2D magnetic materials.