Prediction of room-temperature multiferroicity in strained MoCr₂S₆ monolayer

The contrasting d-orbital occupation required for ferroelectricity vs ferromagnetism makes it difficult for their coexistence in two-dimensional materials, especially at high temperature. To resolve this intrinsic contradiction, we propose a layered MoCr₂S₆ multiferroics by alloying magnetic Cr element into the ferroelectric 1T phase of the MoS₂ matrix. First-principles calculations disclose that a spontaneous symmetry breaking, depending on the Mo atom displacement, leads to a robust ferroelectricity, which coexists with a ferromagnetic order originated from two neighboring Cr atoms. The effect can be further enhanced by tensile strain to bring about a room-temperature multiferroicity. Our findings shed new light on the fundamental understanding of multiferroics and display promising applications in spintronics and multistate data storage.