L.Z. Zhang *, S.C. Xing, T. He, W.-B. Wu, A.-L. Zhang, Z.B. Guo, P. Das, S.H. Zheng, J.-Y. Ge *, X.L. Feng *, Z.M. Sun * and Z.-S. Wu *

Advanced Materials, 2024, Accepted.

The rapid development of low energy dissipation spintronic devices has stimulated the search for air-stable two-dimensional (2D) nanomaterials possessing room-temperature ferromagnetism. Here we report the experimental realization of 2D Mo4/3B2 nanosheets with intrinsic room-temperature ferromagnetic characteristics by vacancy engineering. These nanosheets are synthesized by etching the bulk MAB phase (Mo2/3Y1/3)2AlB2 into Mo4/3B2 nanosheets in ZnCl2 molten salt. The Mo4/3B2 nanosheets show robust intrinsic ferromagnetic properties, with a saturation magnetic moment of 0.044 emu/g at 300 K, while vacancy-free MoB MBene exhibits paramagnetism. We elucidate that the Mo-vacancy defect generates large density of states near the Fermi surface and spontaneously spin-split bands through First-principles calculations, which contributes to the non-zero magnetic moment in Mo4/3B2 nanosheets. Our work lays the groundwork for activating the magnetic properties of MBene nanosheets by vacancy engineering, offering the possibilities for development of practical spintronic devices.