Effect of strain on the magnetic states of transition-metal atoms doped monolayer WS₂

The effects of transition-metal atoms doping and elastic strain on the magnetic properties of monolayer WS₂ are investigated by the first-principles calculation. Firstly, we investigate the magnetic properties of a series of 3d transition-metal atoms (from Sc to Zn) doped monolayer WS₂. Our calculations show that doping of transition-metal atoms from Sc to Cr results in nonmagnetic states, while Mn, Fe, Co, Ni, Cu and Zn doping can induce magnetism in WS₂ monolayer. The localized nonbonding 3d electrons of TM atoms lead to the formation of magnetic moments. Meanwhile, our calculations indicate that the elastic strain can be used to manipulate the spin polarization of TM-3d orbital. Specifically, the magnetic moment of Fe and Co-doped monolayer WS₂ increase with the increase of tensile strain, while the magnetic moment of Mn, Ni, Cu and Zn-doped WS₂ monolayer initially increase and then decrease with the increase of tensile strain. On the other hand, the magnetic moment of Fe, Co, Mn, Ni, Cu and Zn-doped WS₂ monolayers decrease with the increase of compressive strain. While the magnetic moment of Sc, Ti, V and Cr-doped WS₂ monolayers remain 0μ_B independent of tensile strain and compressive strain.