Electronic and magnetic properties of X-doped (X=Ni, Pd, Pt) WS2 monolayer

• WS2 monolayer doped by Ni, Pd and Pt is ferromagnetic.
• The formation energy is lower under S-rich conditions.
• Ni-doped system owns wide half-metallic gap and the lowest formation energy.
• Ni-doped WS2 is the most ideal for spin injection among Ni, Pd, and Pt.

We investigate the electronic and magnetic properties of X-doped (X=Ni, Pd, Pt) WS2 monolayer using the first-principles methods based on density functional theory. The results show that WS2 monolayer doped by Ni, Pd and Pt is ferromagnetic. The impurity states near the Fermi level depend highly on the atomic size and electronegativity. For different X-doped WS2, the formation energy is lower under S-rich conditions, which indicates that it is energy favorable and relatively easier to incorporate X atom into WS2 under S-rich experimental conditions. Moreover, Ni-doped system owns the lowest formation energy compared with other atoms under S-rich experimental condition. Our studies predict X-doped (X=Ni, Pd, Pt) WS2 monolayers to be candidates for thin dilute magnetic semiconductors. Ni-doped WS2 has relatively wide half-metallic gap. So Ni-doped WS2 is the most ideal for spin injection among Ni, Pd, and Pt, which is important for application in semiconductor spintronics.