The magnetism of two-dimensional non-magnetic borides Mo2B2 induced by doping and adsorption

Abstract

To explore the magnetic properties of two-dimensional non-magnetic borides Mo₂B₂ and expand their applications in the field of spintronics, we investigate, based on first-principles calculations, the electronic structures and magnetic properties of Mo₂B₂ monolayers doped and adsorbed with transition metal (TM = V, Cr, Mn, Fe, Co, Ni) atoms. The results show that both TM-doped and TM-adsorbed Mo₂B₂ monolayers retain metallic properties. Specifically, the Cr-, Mn-, and Fe-doped Mo₂B₂ monolayers exhibit ferromagnetism, with magnetic moments of 1.35 μB, 1.92 μB, and 0.97 μB, respectively. Similarly, when Cr, Mn, Fe, and Co atoms are adsorbed onto the Mo₂B₂ monolayer, these systems also display spin polarization, with magnetic moments of 2.37 μB, 1.70 μB, 1.81 μB, and 1.37 μB, respectively. The ferromagnetism primarily originates from the exchange splitting of the d-orbit of these transition metal atoms. The adsorption of TM atoms on Mo₂B₂ monolayer can induce stronger magnetism than doping. Finally, the positive magnetic anisotropy energies (MAE) of Cr/Mn/Fe-doped and Cr/Mn-adsorbed Mo₂B₂ monolayers indicate in-plane magnetization direction, while the negative MAE of Fe and Co atoms adsorbed on Mo₂B₂ monolayers demonstrate that the magnetization direction tends to be perpendicular to the plane. The MAE of Mn- and Fe-doped Mo₂B₂ monolayers have relatively high values of 7130 μeV and 7990 μeV. Our study provides valuable guidance for experimental work.