Intrinsic Valley Polarization in Computationally Discovered Two-Dimensional Ferrovalley Materials: LaI₂ and PrI₂ Monolayers

Ferrovalley materials with intrinsic valley polarization present a novel space for materials exploration suitable for valleytronic applications. Here, two Ferrovalley materials, LaI₂ and PrI₂ monolayers, exhibiting intrinsic valley polarizations of 28 and 35 meV, respectively, mediated by strong magnetic exchange interaction and spin-orbit coupling are computationally discovered. The unconstrained crystal structure prediction algorithm is used to predict the structures of bulk LaI₂ and PrI₂, which are layered and analogous to the 2H phase of transition metal dichalcogenides. The monolayers have small exfoliation energy (smaller than MoS₂) and exhibit dynamical, mechanical, and thermodynamical stability, advocating their experimental realization. Valley polarization under the effect of bi-axial strain is preserved and can be used to enhance valley splitting. Finally, the anomalous hall properties of both the monolayers under the effect of in-plane electric field are discussed. Both the materials exhibit significant anomalous Hall conductivity with proper tuning of the Fermi level.