Strain-Induced Magnetism in MSi2N4 (M = V, Cr): A First-Principles Study

The discovery of ferromagnetic 2D van der Waals (vdW) materials has opened up opportunities for exploring and harnessing magnetism in low-dimensional limit, and developing innovative paper-like spintronic devices. Stress engineering demonstrates unique advantages in regulating material properties, especially for 2D materials. With the aid of first-principles calculations, the effectiveness of strain engineering for modulating the electronic and magnetic properties of MSi2N4 (M = V, Cr) monolayers from a new family of layer-structured 2D vdW materials is explored. Their magnetic configurations are effectively tuned via the uniaxial and biaxial tensile strain of in-plane lattice vectors. VSi2N4 exhibits half-metallic ferromagnetic character, whereas CrSi2N4 is prone to be antiferromagnetic (AFM), which is rationalized from the competition between the direct metal-metal AFM interaction and the 90(0) ferromagnetic superexchange. More intriguingly, VSi2N4 demonstrates a high magnetic ordering temperature of 285 K, which is close to room temperature. The predicted appealing properties of VSi2N4 under strain await experimental confirmation.

Automated summary

The effectiveness of strain engineering in modulating the electronic and magnetic properties of MSi2N4 (M = V, Cr) monolayers, from a new family of layer-structured 2D vdW materials, was explored. VSi2N4 exhibits half-metallic ferromagnetic character, whereas CrSi2N4 is prone to be antiferromagnetic.