Raising the Curie Temperature of Two-Dimensional Semiconducting CrSbr by van der Waals Coupling with In-Plane Ferroelectric GeS

For most multiferroics, the combination of ferromagnetism and ferroelectricity holds unprecedented promise for high-density and low-power polymorphic storage. In contrast to single-phase multiferroics, which cannot achieve strong magnetoelectric coupling at room-temperature, heterostructure coupling is an effective strategy. In this work, based on first-principles calculations, the magnetoelectric coupling in the CrSBr/GeS heterostructure is investigated. As a representative of 2D ferromagnetic materials, CrSBr can be exfoliated from a layered bulk crystal, but its Curie temperature (T C ) remains well below room temperature. GeS is an experimentally preparable ferroelectric semiconductor with in-plane polarization. The interfacial coupling in the heterostructure not only facilitates charge transfer but also provides a new exchange coupling path for Cr in the ferromagnetic CrSBr, further increasing the T C of the magnetic system. In addition, both in-plane strain and back-gate electric field can regulate the electric polarization intensity of FE GeS, which further affects the charge distribution and coupling of the interface and changes the T C of the magnetic layer. With a 5% tensile strain along the a-axis direction, the T C of CrSBr increases to 246 K, while the in-plane polarization of GeS decreases to 3.71 x 10-10 C/m. These results show that CrSBr/GeS multiferroic heterostructures provide a multiknob research platform for magnetoelectric coupling and high-density memory devices.