Theoretical study of tunable magnetism of two-dimensional MnSe2 through strain, charge, and defect

Two-dimensional transition metal dichalcogenide MnSe2 (2D-MnSe2) with Curie temperature approximate to 300 K has a significant spintronic application on thin-film devices. We demonstrate theoretically a tunable magnetic transition of 2D-MnSe2 between anti-ferromagnetic (AFM) metal and ferromagnetic (FM) half metal as strain increasing. Mechanism of that transition involves a competition between d-p-d through-bond and d-d direct interaction in 2D-MnSe2. Hole doping is an alternative way to enhance the stability of FM coupling. Adsorption (including Li, Na, Cl and F) and vacancy (Mn and Se) studies confirm that the controllable magnetism of 2D-MnSe2 is related to both interaction competition and charge doping. Tensile strains can greatly amplify through-bond interaction and exchange parameters, resulting in a sharp increase of Curie temperature.