Half-metallicity and enhanced magnetism in monolayer T-CrTe2 by lithium adsorption

Based on first-principle calculations, we investigate the electronic and magnetic properties of Li-adsorbed monolayer T-CrTe2, named LixCrTe2. We find that as the adsorption concentration x increases from 0.25 to 1.0 and then to 1.25, the monolayers change from metal to semiconductor and then to half-metal. We demonstrate that Li adsorption tuning the electronic properties mainly through electron doping and lattice expansion. The former raises the band filling level, while the latter significantly enhances the ferromagnetic coupling and help open energy gaps. Besides, we find the Curie temperature qualitatively increases as x increases from 0.25 to 1.0 and then decreases at x=1.25, which is caused by the joint effect of the direct exchange, the superexchange and the increased band filling level. Our work provides an efficient strategy to tailor magnetism and produce two-dimensional magnetic semiconductors and half-metals from metals.