Triferroic coupling in two-dimensional WRuCl6

In this work, we report that electrically controlled ferroic properties and multistate storage can be achieved in dual-metal trihalide WRuCl₆ monolayer from the perspectives of first-principles calculations. We confirm that it is a rare two-dimensional (2D) triferroics, and, particularly, ferromagnetism and ferroelasticity are coupled strongly to the ferroelectricity of 120 ^∘{} rotation symmetry. It therefore can enable the flexible and reversible switching of ferroic orders via electric field. In addition, WRuCl₆ monolayer is an intrinsic bipolar magnetic semiconductor; thus, the switchable spin-polarized carrier can be obtained by applying an electric gate voltage. Therefore, it provides an extra parameter to further improve the storage density. Our work not only offers a paradigm for the multiferroic coupling physics, but also provides a promising platform for multistate storage and multifunctional nanodevices.