Manipulate Electronic and Magnetic Properties of Two-Dimensional Manganese Chalcogenides via Hydrogenation

Two-dimensional (2D) antiferromagnetic manganese chalcogenides have been successfully synthesized recently. However, the electronic and magnetic properties of these new materials have not been clearly understood. The absence of net magnetization and a large electronic band gap may hinder their application. In this work, we systematically studied the electronic and magnetic properties of the semihydrogenated MnX (donated as H@MnX, X = S, Se, Te) monolayers. The hydrogen atoms can stably adsorb onto the Mn ions. In the hydrogenated Mn sublayer, the magnetic couplings between adjacent Mn ions become ferromagnetic, while the magnetic couplings in the other Mn sublayer and the intersublayer magnetic couplings remain antiferromagnetic. Consequently, the magnetic ground state becomes ferrimagnetic, with a net magnetic moment of 0.5 mu B per Mn. The critical temperatures of the ferrimagnetic order for H@MnSe and H@MnTe are similar to 180 and similar to 200 K, respectively. Semihydrogenation also greatly changes the electronic structures of MnX. The electronic band gaps of MnX monolayers are reduced from 3.87, 3.41, and 3.09 eV to 1.21, 0.66, and 0.25 eV, respectively. Particularly, H@MnTe exhibits a direct band gap. A biaxial inplane strain can further tune the magnetic behaviors of the H@MnX monolayers. These findings provide a practical route to manipulating the electronic and magnetic properties of 2D magnetic semiconductors for advanced spintronic applications.