Spin‐Dependent Electronic Structure and Magnetic Anisotropy of 2D Ferromagnetic Janus Cr2I3X3 (X = Br, Cl) Monolayers

Abstract Two‐dimensional (2D) Janus monolayers with mirror asymmetry have been found to possess extraordinary physical characteristics, meaning they could find applications in optoelectronic, electronic, and electromechanical devices. However, 2D Janus materials with intrinsic magnetism are rare. The electronic structure and magnetic properties of Janus Cr 2 I 3 X 3 ( X = Br, Cl) monolayers are investigated by first‐principles calculations. Janus Cr 2 I 3 X 3 monolayers are an indirect band gap semiconductor with good stability, intrinsic ferromagnetism, and electric polarization. Cr 2 I 3 Br 3 monolayer is a half semiconductor with perpendicular magnetic anisotropy (PMA), while Janus Cr 2 I 3 Cl 3 monolayer is a bipolar magnetic semiconductor with in‐plane magnetic anisotropy (IMA). The band gap and Cr magnetic moment of Janus Cr 2 I 3 X 3 monolayers can be tailored by biaxial strain. Additionally, a strain‐induced transition from half semiconductor to bipolar magnetic semiconductor, and reversal between PMA and IMA, appears in the Janus Cr 2 I 3 X 3 monolayers. These results enrich the diversity of Janus 2D materials, which have potential applications in 2D spintronic devices.