Two-dimensional intrinsic ferrovalley GdI2 with large valley polarization

Manipulation of the valley degree of freedom provides a novel paradigm in quantum information technology. In this work, through first principles calculations, we demonstrate that monolayer $\mathrm{Gd}{\mathrm{I}}_{2}$ is a promising candidate material for valleytronic applications. Monolayer $\mathrm{Gd}{\mathrm{I}}_{2}$ can be easily exfoliated from bulk, and it is spontaneously valley polarized with a giant splitting of 149 meV due to its intrinsic ferromagnetism and large spin orbital coupling. The anomalous valley Hall effect could be realized in monolayer $\mathrm{Gd}{\mathrm{I}}_{2}$ by an appropriate external electric field. Furthermore, the valley polarization feature is stable against the biaxial in-plane strain. Our findings provide an extraordinary and potential material platform for experimental studies and practical applications in the emergent field of valleytronics.