GdIMH (M = S, Se) monolayers: 2D bipolar magnetic semiconductors

In this study, we predict a class of two-dimensional f -electron bipolar magnetic semiconductors, GdIMH ( M = S , Se ), using first-principles calculations. Monolayer GdIMH has excellent dynamic and thermal stability, higher magnetic anisotropy, and in-plane easy magnetic plane. Notably, it is also a field-induced ferrovalley material. When magnetizing along the out-of-plane direction, the combination of ferromagnetic and spin-orbit coupling effects induces a valley polarization as high as 163 meV and the Berry curvature values at the K and K ′ valleys exhibit opposite signs with different absolute values. Furthermore, under this out-of-plane magnetization, biaxial strain can further enhance the valley splitting and magnetic anisotropy energy, while charge doping can realize the transition from a bipolar magnetic semiconductor to a half-metal. These results indicate that the GdIMH monolayer is a potential multifunctional 2D f -electron ferromagnet.