First‐principles study of the novel two-dimensional monolayer VAl2S4 with half-metallic properties

A novel two-dimensional half-metallic monolayer VAl₂S₄ with 100 % spin polarization is proposed and studied based on first-principles calculations. The stability has been systematically validated through phonon dispersion spectrum, molecular dynamics simulations, cohesive energy, formation energy, elastic constants, and the electron localization function. The VAl₂S₄ monolayer also maintains intrinsic structural stability under its own gravitational influence. The calculations demonstrate that the half-metallic character of the material remains robust under biaxial strain ranging from −3 % to +2 %. When Hubbard correction is considered, depending on the different values of U chosen, the VAl₂S₄ monolayer can exhibit extremely rich physical properties, such as half-metal, spin gapless semiconductor, and bipolar magnetic semiconductor. The studies on magnetic anisotropy indicate that the VAl₂S₄ monolayer has relatively large magnetic anisotropy energy within the xy plane. The high spin polarization, stable half-metallicity, relatively high magnetic anisotropy energy exhibited by the VAl₂S₄ monolayer, as well as the extremely rich physical properties it shows under the Hubbard correction, endowing it with great application potential in the fields of spin-logic devices and high-density magnetic storage.