Magnetic and Electric Properties and Their Regulation of the Intrinsic Half‐Metallic Multiferroic Monolayers AV2S4.

2D half‐metallic multiferroic materials have attracted great interest due to their rich novel performances and wide application prospect in nanoelectronics and nanodevices. Three intrinsic half‐metallic multiferroic monolayers AV2S4 (A = Na, K, and Rb) are predicted based on the first‐principles calculations. From the calculations, their ground states are all ferromagnetic and are completely spin‐polarized at the Fermi level. Their total magnetic moments are always 3.00 μB per primitive cell, which origin mainly from V‐ions. The two‐center electronic structure t2g6↑t2g4↓eg1↑ of V‐ions is proposed from the perspective of the crystal field theory to explain successfully the calculated magnetic moments. Interestingly, the alkali‐metal ions are non‐magnetic, but they may cause important influence on the magnetic coupling between transition ions, and then the half‐metallicity of these monolayers. Their electric and magnetic properties may be tuned by their charge states and strains. Especially, their half‐metallic stability may be evidently improved by the tensile strains. The half‐metallic gaps of these monolayers may be increased by about 67.4%, 50.8%, and 32.4% for NaV2S4, KV2S4, and RbV2S4 by the tensile strain 2.0%, respectively. [ABSTRACT FROM AUTHOR]