First-Principles Study of Induced Magnetism in Tungsten Vanadium Selenide Alloys for Spintronic Applications

The possibility of inducing magnetization in tungsten selenide monolayer by alloying with vanadium selenide was investigated through first-principles calculations. Electronic, optical, and magnetic properties of different W_1- V Se₂ alloy compositions were studied extensively. As the proportion of vanadium atoms in the alloys increased, a phase transition from semiconducting to metallic to semiconducting was discovered. All alloy compositions demonstrated induced magnetism with a long-range ferromagnetic order. Interestingly, in the case of the W_0.25V_0.75Se₂ alloy, spin-up states in the band diagram showed a finite band gap, while a nonzero band gap was found for spin-down states. The W_0.25V_0.75Se₂ alloy can be used as a spin filter tunneling barrier exploiting this fascinating property. High spin polarization of the tunnel current was found for the alloy. Furthermore, under the Curie temperature, electrical conductivity for the spin-up channel was found to be zero, while conductivity for the spin-down channel was around 10¹⁹ (Ω cm s)^-1 when the chemical potential was 0.2 eV greater than the Fermi energy. Changes in optical properties were also investigated through time-dependent density functional theory calculations. The findings of this study will be beneficial for proposing new magnetic monolayer alloys for application in nanoscale spintronic devices.