Coexistence of Magnetism and Ferroelectricity in 3d Transition-Metal-Doped SnTe Monolayer

The multiferroicity in two-dimensional materials is crucially important for potential high-density storage devices. On the basis of the recent synthesis of ferroelectric SnTe, we predict the coexistence of ferromagnetism and ferroelectricity in monolayer SnTe system by transition-metal (TM)-doping engineering. With the state-of-the-art first-principles calculations, we report the ferromagnetic configurations in TM-doped ferroelectric SnTe monolayer. Although the large distortion is introduced by dopants, the in-plane ferroelectric polarization still remains in Mn (Fe)-doped SnTe monolayer. More interesting, the out-of-plane ferroelectric polarization spontaneously emerges in Mn (Fe)-doped SnTe monolayer, contributing from the internal displacement of the TM dopants. Thus, our findings provide viable guidance for the realization of low-dimensional multiferroic materials.