Prediction of room-temperature antiferromagnetism in V2CT2 (T = Cl, Br, I) MXenes

Abstract

The search for two-dimensional (2D) magnetic materials has attracted considerable attention in both experimental and theoretical research due to their distinctive properties and potential applications in spintronic devices. Although many 2D materials exhibiting magnetic order have been discovered, room-temperature 2D ferromagnetic (FM) materials remain scarce, and 2D materials with antiferromagnetic (AFM) order are even more rarer. In this manuscript, we propose an effective strategy to achieve high Néel temperatures T_c in 2D AFM materials by designing interlayer superexchange coupling. Through first-principles calculations, we identify V₂CT₂ (T = Cl, Br, I) MXenes as dynamically stable materials with strong exchange coupling interactions. To determine their T_c, we developed a Monte Carlo (MC) simulation code, spins2, accelerated with Numba. Our results show that V₂CT₂ MXenes are promising candidates for room-temperature AFM materials, with predicted T_c values of 590, 550, and 420 K for Cl, Br, and I terminations, respectively. Furthermore, we demonstrate that T_c can be tuned linearly by applying strain along the y-axis, offering a versatile approach for tailoring their magnetic properties.