Evidence of the existence of magnetism in pristine VX₂ monolayers (X = S, Se) and their strain-induced tunable magnetic properties.

First-principles calculations are performed to study the electronic and magnetic properties of VX(2) monolayers (X = S, Se). Our results unveil that VX(2) monolayers exhibit exciting ferromagnetic behavior, offering evidence of the existence of magnetic behavior in pristine 2D monolayers. Furthermore, interestingly, both the magnetic moments and strength of magnetic coupling increase rapidly with increasing isotropic strain from -5% to 5% for VX(2) monolayers. It is proposed that the strain-dependent magnetic moment is related to the strong ionic-covalent bonds, while both the ferromagnetism and the variation in strength of magnetic coupling with strain arise from the combined effects of both through-bond and through-space interactions. These findings suggest a new route to facilitate the design of nanoelectronic devices for complementing graphene.