First principles investigation of the Co(0001)/MoS2 and Ni(111)/WSe2 interfaces for spin injection in a transition metal dichalcogenide monolayer

The hexagonal close-packed ( hcp ) Co(0001)/MoS 2 and face-centered cubic ( fcc ) Ni(111)/WSe 2 interface atomic, magnetic and electronic structures are investigated using first-principles methods based on the density functional theory. We show that the MoS 2 and WSe 2 single layers are covalently bond to the Co(0001) and Ni(111) metal surfaces. We describe the consequences of this bonding on the spin magnetic moments and on the electron states at the vicinity of these interfaces, where MoS 2 and WSe 2 become metallic due to hybridization between Co (or Ni) and S (or Se) atomic orbitals. A finite spin-polarization at the Fermi level is calculated in the MoS 2 and WSe 2 layers at these two interfaces. We also give and estimation of the Schottky barrier height that may appear at the border between the metallic and semiconducting phases of MoS 2 (or WSe 2 ) near the edge of a Co/MoS 2 or Ni/WSe 2 metallic contact.