Magneto-optical Kerr effect and magnetoelasticity in a weakly ferromagnetic RuF4 monolayer

Considerable research interest has been attracted to noncollinear magnetic\nstructures for their intriguing physics and promising applications. In this\nwork, based on relativistic density functional theory, we reveal the\ninteresting magnetic order and relevant properties in monolayer RuF$_4$, which\ncan be exfoliated from its bulk phase. Although the spins on Ru ions are almost\nantiferromagnetically aligned between nearest-neighbors, weak ferromagnetism is\ngenerated because of the antisymmetric Dzyaloshinskii-Moriya interaction as\nwell as the single-ion anisotropy. A prominent magneto-optical Kerr effect can\nbe observed for this antiferromagnet, similar to those of regular strong\nferromagnets. In addition, a uniaxial strain can induce a ferroelastic\nswitching together with the in-plane rotation of spin direction, giving rise to\na strong intrinsic magnetoelasticity. Our work not only suggests an alternative\ndirection for two-dimensional magnetic materials, but also provides hints to\nfuture devices based on antiferromagnetic magnetoelastic or magneto-optical\nmaterials.\n