Half-metallicity and enhanced ferromagnetism in Li-adsorbed ultrathin chromium triiodide

Two-dimensional materials with robust magnetism have been a long-sought goal because of their potential applications in information technology. Very recently, intrinsic ferromagnetic chromium triiodide (CrI3) was reported down to monolayer experimentally (B. Huang, et al., Nature, 2017, 546, 270). Herein, based on first-principles calculations, we show that the CrI3 monolayer can be switched from semiconducting to half-metallicity by lithium atom adsorption. The half-metallicity can be well preserved regardless of the Li concentration or the thickness of the CrI3 sheet. Moreover, the adsorption of Li atoms can further enhance the ferromagnetism of CrI3 sheets by increasing both the magnetic moment and the Curie temperature. The robust half-metallicity together with improved ferromagnetism may open up new promising applications of CrI3-based materials in spintronics.