Robust p-orbital half-metallicity and high Curie-temperature in the hole-doped anisotropic TcS2 (X=S, Se) nanosheets

Abstract: Here, we study the magnetism of the distorted 1T-TcX2 (X=S,Se) based on first-principles calculation. The magnetism originates from the hole doping due to the density of states near the valence band edge having van Hove singularity feature. The calculated results show that the TcS2 monolayer can develop an interesting ferromagnetic (FM) half-metallic phase with tunable spin-polarization orientation. The FM half-metallicity and magnetic moments of the hole-doped TcS2 monolayer are primarily derived from the p orbital of S atoms, then, a FM ground phase with a high Curie temperature (Tc) (larger than 800 K) is obtained due to the strong Sp-Sp direct exchange interaction. The magnetic order is robust against thermal excitations at finite temperatures because of magnetic anisotropic energy. In the TcS2 bilayer, the electrons near Fermi level are redistributed when introducing the interlayer interaction, which suppresses the ferromagnetism induced by hole doping. The ferromagnetism can be recovered when the interlayer interaction is weakened.