First-principles calculations to investigate electronic structures, ferromagnetic and optical properties of SnSe2 doped with double impurities

The electronic structures, ferromagnetic and optical properties of pure SnSe2, Fe doped SnSe2, Mo doped SnSe2 and (Fe, Mo) co-doped SnSe2 are studied by the first-principles calculations of the GGA + U methods. The calculation results indicate that the introduction of Fe and Mo atoms can induce total magnetic moments of 4 mu(B) and 1.98 mu(B), respectively. However, there is a stable ferromagnetic state with Delta E value of about -538.7 meV for (Fe, Mo) co-doped SnSe2, and the ferromagnetic state is resulted from the powerful hybridisation of Fe:3d, Mo:4d and Se:4p orbitals. With the addition of transition metals Fe and Mo, the band gap is gradually reduced but the conductivity is increased. In addition, the addition of Fe and Mo increases the spectral value of the system in visible light, and the addition of Fe can make up for the deficiency of pure SnSe2 in infrared light absorption. Besides, the doping system has a low transmittance in the infrared region. In short, the Fe, Mo doped SnSe2 are helpful to make it to be excellent candidate material in ferromagnetic and photoelectricity fields.