Magnetic and optical properties of (Fe, Mn) co-doped SnSe2 monolayer: A first-principles study

The magnetic and optical properties for double impurities (Fe, Mn) doped SnSe2 are investigated by first principles calculations. We calculate that the magnetic moments of Fe and Mn for Fe and Mn mono-doped SnSe2 are 3.98 mu B and 4.97 mu B, respectively. In the GGA + U method, the ferromagnetism of the (Fe, Mn) co-doped SnSe2 system prefers the most stable state, which is resulted from the hybridization between Fe:3d, Mn:3d and Se:4p states. In addition, we apply strain to research the magnetism for the (Fe, Mn) co-doped SnSe2 system in the GGA + U method. We find that the structure of molecule are changed by strain and the ferromagnetism of (Fe, Mn) co doped SnSe2 is also significantly improved. The introduction of transition metal (TM = Fe, Mn) can effectively improve electric conductivity. And the adsorption strength of TM doped SnSe2 is also outstanding enhanced. The deficiency of ultra violet absorption in the doped system is compensated under strain. These results indicate the (Fe, Mn) co-doped SnSe2 will be a perfect candidate for spintronic devices applications.