Defect states in magnetically "seasoned" WSSe - adsorption and doping effects of magnetic transition metals X = V, Cr, Mn, Fe, Co - a comprehensive first-principles study.

Besides the symmetry breaking of Janus transition metal dichalcogenides (TMDs), Janus-based Diluted Magnetic Semiconductors (DMS) are attractive to study considering the local symmetry of transition metal (TM) dopant/adatom. This study conducts a first-principles calculation of magnetic properties in TM (V, Cr, Mn, Fe, and Co) -- doped and adsorbed Janus WSSe. Our results reveal that TM's atomic/ionic size impacts d-p-d orbital overlap, affecting bond length/angle and defect state positions. The result shows that V-doped WSSe exhibits long-range ferromagnetic order sustained by itinerant carriers and W atom spin-orbital coupling (SOC). The mechanism of d-p-d orbital hybridization is highlighted with an overlapping density of states and spin-density plots. Moreover, an enhanced magnetic anisotropy energy (MAE) is observed in Fe/Co-doped and Mn/Fe-adsorbed systems, with the easy axis aligning to the c-axis. The orbital contribution of MAE provided explains the relationship between states near the Fermi and MAE. On the other hand, the adsorption of V and Cr aligns the easy axis to the a-b plane, for which we have systematically explained the contribution of the spin-flip term in MAE. This research provides insights and a guideline for further exploration of 2D DMS for spintronics and spin-related phenomena.