Defect induced magnetism in monolayer HfSe2: An ab initio study

In this article, we report systematic studies of vacancy defects and substitutional defects on the electronic and magnetic properties of HfSe₂ monolayer using first-principles calculations. It is found that the monolayer of semiconducting HfSe₂ supercell (4 × 4 matrix) becomes metallic on creating a single Se/Hf site vacancy, as well as a pair of vacancies at Hf and Se sites; while it remains semiconducting on creating a Schottky vacancy with an increased band gap value. Magnetic investigations show that a magnetic moment develops on the supercell for single Hf site vacancy and a pair of Hf and Se site vacancies. With a substitutional defect at Hf site by 4d/5d transition metal in monolayer HfSe₂, it becomes magnetic with the highest magnetic moment for Tc (4d) and Re (5d) doping. It is noted that monolayer of the HfSe₂ supercell becomes half-metallic for Nb, Mo, and W doping. The detailed defect studies of monolayer HfSe₂ provide an opportunity for its applications in spintronics.