Modulation of Spin Polarization and Magnetic Ordering in MSe₂/WSe₂ (M= 3d Transition Metal Atom) Structure: A First-Principles Study

The ability to tailor the electronic and magnetic properties of two-dimensional (2D) materials opens new avenues for designing spintronic devices. In this study, first-principles calculations have been performed to investigate the structural, electronic, and magnetic properties of bilayer tungsten diselenide (WSe2) doped with a 3d transition metal atom. Among the two different stacking configurations considered (AA and AA′) for bilayer WSe2, the AA′ stacking configuration has been identified as energetically favorable and dynamically stable. Doping one layer of the bilayer system MSe2/WSe2 (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, and Cu) significantly alters the electronic structures and induces finite magnetic ordering in the structures. The doped atom exhibits strong binding with neighboring Se atoms, having binding energies ranging from −2.73 eV to −6.36 eV, confirming robust structural stability. The Mn-doped structure attains a maximum magnetic moment of 3.63 μB in its ferromagnetic state, though its antiferromagnetic state is energetically more favorable. Strain engineering further enhances the magnetic moment in the Mn-doped structure to 4.00 μB, highlighting the tunability of the system. On the other hand, the Cr-doped structure exhibits ferromagnetic ordering in its ground state with a magnetic moment of 2.48 μB. Utilizing the modified mean-field theory and Heisenberg model, the maximum Curie temperature has been approximated as 159.94 K for the CoSe2/WSe2 configuration, while the maximum Neel’s temperature is estimated to be 367.67 K for the FeSe2/WSe2 configuration. The findings of this work establish a strong theoretical foundation for designing 2D materials with tunable magnetic properties, paving the way for further experimental exploration and next-generation spintronic device applications.