Multiferroic monolayers VOX (X = Cl, Br, I): tunable ferromagnetism via charge doping and ferroelastic switching


 The fascinating properties arising from the interaction between different ferroic states of two-dimensional (2D) materials are inspiring tremendous research interest in the past few years. Under the first-principles calculations, we predict the coexistence of antiferromagnetic and ferroelastic states in VOX (X = Cl, Br, I) monolayers. The results illustrate that VOX monolayers exhibit indirect bandgap characteristics with the gaps decreasing with the halide elements changing from Cl to I. The ground states of all these VOX monolayers are antiferromagnetism (AFM) with the magnetic moments donated by the V 3d electrons. What’s more, the magnetic ground state change from AFM to ferromagnetism (FM) can be realized by doping carriers. In addition, the moderate ferroelastic transition barrier and reversible switching signal guarantee their high performance of nonvolatile memory devices. Our findings not only offer an ideal platform for the investigation of multiferroic properties, but also provide candidate materials for potential applications in spintronics.