Tunable intrinsic magnetism in 2D Mo2B2 via double-transition-metal engineering under electric field and hole doping

Abstract

To advance the exploration of two-dimensional (2D) magnetic materials for spintronic applications, we propose a family of double-transition-metal (DTM) boride monolayers, MMoB2 (M = V, Cr, Mn, Fe, Co, Ni), and systematically investigate their magnetic behaviors using first-principles calculations combined with Monte Carlo simulations. Our study demonstrates that intrinsic magnetism is achieved in MMoB2 (M = V, Cr, Mn, Fe, Co, Ni) monolayers except NiMoB2. The magnetic moments in MMoB2 (M = V, Cr, Mn, Fe, Co) monolayers primarily originate from the exchange splitting of the M atoms' d-orbitals. MMoB2 (M = V, Cr, Mn) monolayers show an out-of-plane easy magnetization axis, while MMoB2 (M = Fe, Co) monolayers exhibit an in-plane easy axis. The calculated Curie temperatures (TC) of MMoB2 (M = V, Cr, Mn, Fe) monolayers significantly higher than room temperature, with the CrMoB2 monolayer reaching up to 1174 K, making them highly promising candidates for practical spintronic applications. In addition, both vertical electric fields and hole doping effectively manipulate the magnetic behaviors of MMoB2 (M = V, Cr, Mn, Fe, Co) monolayers. Under these external stimuli, the magnetic moments, magnetic anisotropy energies (MAE) and TC of MMoB2 (M = V, Cr, Mn, Fe, Co) monolayers are further enhanced.