Iron-doping induced multiferroic in two-dimensional In2Se3

Multiferroic materials exhibit tremendous potentials in novel magnetoelectric devices such as high-density non-volatile storage. Herein, we report the coexistence of ferroelectricity and ferromagnetism in two-dimensional Fe-doped In2Se3 (Fe0.16In1.84Se3, FIS). The Fe atoms were doped at the In atom sites and the Fe content is ~3.22% according to the experiments. Our first-principles calculation based on the density-functional theory predicts a magnetic moment of 5 µB per Fe atom when Fe substitutes In sites in In2Se3. The theoretical prediction was further confirmed experimentally by magnetic measurement. The results indicate that pure In2Se3 is diamagnetic, whereas FIS exhibits ferromagnetic behavior with a parallel anisotropy at 2 K and a Curie temperature of ∼8 K. Furthermore, the sample maintains stable room-temperature ferroelectricity in piezoresponse force microscopy (PFM) measurement after the introduction of Fe atom into the ferroelectric In2Se3 nanoflakes. The findings indicate that the layered Fe0.16In1.84Se3 materials have potential in future nanoelectronic, magnetic, and optoelectronic applications.