Electronic and Magnetic Properties of Defected Monolayer WSe₂ with Vacancies

By adopting the first-principle methods based on the density functional theory, we studied the structural, electronic, and magnetic properties of defected monolayer WSe₂ with vacancies and the influences of external strain on the defected configurations. Our calculations show that the two W atom vacancies (V_W2) and one W atom and its nearby three pairs of Se atom vacancies (V_WSe6) both induce magnetism into monolayer WSe₂ with magnetic moments of 2 and 6 μ_B, respectively. The magnetic moments are mainly contributed by the atoms around the vacancies. Particularly, monolayer WSe₂ with V_W2 is half-metallic. Additionally, one Se and one W atom vacancies (V_Se, V_W), two Se atom vacancies (V_Se-Se), and one W atom and the nearby three Se atoms on the same layer vacancy (V_WSe3)-doped monolayer WSe₂ remain as non-magnetic semiconducting. But the impure electronic states attributed from the W d and Se p orbitals around the vacancies locate around the Fermi level and narrow down the energy gaps. Meanwhile, our calculations indicate that the tensile strain of 0~7% not only manipulates the electronic properties of defected monolayer WSe₂ with vacancies by narrowing down their energy gaps, but also controls the magnetic moments of V_W-, V_W2-, and V_WSe6-doped monolayer WSe₂.