Decoupled strain response of ferroic properties in a multiferroic VOCl2 monolayer

Two-dimensional (2D) magnetoelectric multiferroics are promising multifunctional materials for miniaturized logic and memory devices. Herein, we explore the effectiveness of strain engineering for tuning the properties of a recently predicted 2D antiferromagnetic-ferroelectric, ${\mathrm{VOCl}}_{2}$ monolayer. Interestingly, we find that magnetic ordering and electric polarization can be tuned independently using uniaxial tensile strain along different in-plane lattice vectors. A 4% tensile strain along lattice vector $b$ induces a transition from an antiferromagnetic ground state with an out-of-plane magnetization to a ferromagnetic ground state with in-plane magnetization. On the other hand, tensile strain along lattice vector $a$ enhances spontaneous electric polarization, without affecting the magnetic ordering. The monolayers remain dynamically stable under tensile strain, which further helps to raise the Curie temperature of ferromagnetism, as well as ferroelectricity. Such a strain-tunable multiferroic material holds great promise for future generation nanoelectronic devices.