2D Mn2C6Se12 and Mn2C6S6Se6: Intrinsic Room-Temperature Dirac Spin Gapless Semiconductors and Perfect Spin Transport Properties

Two-dimensional intrinsic ferromagnets with high spin polarization and high Curie temperature are rare and very important for developing novel nanoscale spintronic materials and devices. In this work, by using the first-principles calculations, we confirm that Mn 2 C 6 Se 12 and Mn 2 C 6 S 6 Se 6 monolayers are perfect and nearly Dirac spin gapless semiconductors with 100% spin polarization, high Fermi velocities, high Curie temperatures, and large magnetic anisotropic energies. Within the spin–orbit coupling, the Mn 2 C 6 Se 12 monolayer has nontrivial topological properties with a nonzero Chern number, which is confirmed by the calculated Berry curvature, anomalous Hall conductance, and chiral edge states. We also reveal from the first-principles combined with the nonequilibrium Green’s function method that both monolayers exhibit perfect spin transport properties such as the spin-filtering effect, the negative differential resistance effect, and high magnetoresistance. These results suggest that Mn 2 C 6 Se 12 and Mn 2 C 6 S 6 Se 6 monolayers are promising candidates for the realization of the quantum anomalous Hall effect and the 2D spintronic devices.