Intrinsic multiferroicity in molybdenum oxytrihalides nanowires

Low-dimensional multiferroics, which simultaneously possess at least two primary ferroic order parameters, hold great promise for post-Moore electronic devices. However, intrinsic one-dimensional (1D) multiferroics with the coexistence of ferroelectricity and ferromagnetism are still yet to be realized, which will be not only crucial for exploring the interplay between low-dimensionality and ferroelectric/ferromagnetic ordering but also significant in rendering application approaches for high density information technologies. Here, we present a theoretical prediction of intrinsic multiferroicity in 1D molybdenum oxytrihalides nanowires, especially focusing on MoOBr₃ nanowires which could be readily extracted from experimentally synthesized van der Waals MoOBr₃ bulk materials. Due to the spatial inversion symmetry spontaneously broken by Mo atoms’ displacements, MoOBr₃ nanowires exhibit 1D ferroelectricity with small coercive electric field and exceptional Curie temperature (~570 K). Additionally, MoOBr₃ nanowires also possess 1D antiferroelectric metastable states. On the other hand, both ferroelectric and antiferroelectric MoOBr₃ nanowires exhibit ferromagnetic ordering on account of the half-filled Mo-d_yz orbitals, a moderate tensile strain (~5%) can greatly boost the spontaneous polarization (~40%) and a mild compress strain (~−2%) may readily switch the magnetic easy axis of ferroelectric MoOBr₃ nanowires. Our work holds potential candidates for developing innovative devices that exploit intrinsic multiferroic properties, enabling advancements in novel electronic and spintronic applications.