Electronic and Magnetic Properties of Vanadium Dichalcogenides Monolayers Tuned by Hydrogenation

First-principles calculations based on density-functional theory are carried out to systematically investigate the effects of hydrogenation on the electronic and magnetic properties of vanadium dichalcogenides (VX 2, X = S, Se, and Te) monolayers. We find that semimetallic and ferromagnetic VX 2 monolayers can be tuned to be nonmagnetic/antiferromagnetic and intrinsically semiconducting by functionalizing with hydrogen atoms on one of their surfaces, and ferromagnetic/antiferromagnetic and n-type semiconducting when both of their two surfaces are fully covered by hydrogen atoms. The ferromagnetism and antiferromagnetism are contributed to carrier-mediated double-exchange and superexchange, respectively. Ferromagnetism is obtained in semimetallic or lightly doped semiconducting monolayers due to double-exchange of localized spins with static localized states, while antiferromagnetism can be achieved in intrinsic or heavily doped semiconducting monolayer duo to the superexchange interaction. These vanadium dichalcogenides monolayers with hydrogenation may apply to nanodevices, sensors, and spintronics.