Unusual Electronic and Magnetic Properties of Spin‐Sandwich Cr2SexI6‐x

Abstract The modulation of the electronic and magnetic properties of 2D CrI 3 is investigated. The substitutional doping of I with Se impurities can introduce hole carriers and strain, which strongly modulate the physical properties of 2D CrI 3 . The Se impurities are magnetic, with their magnetic direction opposite to that of Cr atoms. Se impurities are very active and contribute shallow impurity bands into the bandgap. As a result, the bandgap of CrI 3 is reduced, and the magnetic exchange interactions between Cr atoms are significantly enhanced. The Curie temperature can be increased up to 250 K, while the large out‐of‐plane magnetic anisotropic energy (MAE) is preserved. The total magnetization, magnetic exchange interactions, and bandgap can be tuned over a wide range by varying the concentration of the Se impurities. Moreover, Se doping enables electronic polarization. The strong magnetoelectric effects of van der Waals (vdW) heterostructures composed of graphene and Janus Cr 2 Se 3 I 3 are also demonstrated.